1.
As the two strands of DNA are unraveled, an enzyme relieves the strain on the two strands. The enzyme is
Correct Answer
C. DNA gyrase
Explanation
DNA gyrase is the correct answer because it is an enzyme that relieves the strain on the two strands of DNA as they are unraveled. This enzyme is responsible for preventing excessive supercoiling of the DNA molecule during replication or transcription. It does this by introducing negative supercoils ahead of the replication fork, which helps to unwind the DNA strands and reduce the strain.
2.
The maintenance of a constant environment of a cell is called
Correct Answer
B. Homeostasis
Explanation
Homeostasis refers to the maintenance of a constant and stable internal environment within a cell. This is achieved through various regulatory mechanisms that ensure the balance of temperature, pH, nutrient levels, and other factors necessary for the cell's proper functioning. Active transport, gene expression, and translation are all important cellular processes, but they do not specifically refer to the maintenance of a constant environment. Therefore, the correct answer is homeostasis.
3.
Recent developments in our understanding of the human genome suggest that while the genome contains approximately 25,000 gene sequences, there are far more different proteins produced by the genome. Which of the following concepts may explain how this occurs?
Correct Answer
C. Alternative splicing may occur, creating different mRNA's from a single stretch of DNA
Explanation
Alternative splicing is a process in which different combinations of exons are selected during mRNA processing, leading to the production of multiple mRNA molecules from a single DNA sequence. This allows for the generation of different protein isoforms from a single gene, increasing the diversity of proteins produced by the genome. This process accounts for the discrepancy between the number of gene sequences and the number of proteins produced.
4.
Regions of noncoding DNA that interrupts the nucleotide sequence of a gene are called
Correct Answer
B. Introns
Explanation
Introns are regions of noncoding DNA that interrupt the nucleotide sequence of a gene. They are transcribed into RNA but are later removed during the process of RNA splicing. Introns do not code for proteins and their presence allows for alternative splicing, which can generate multiple protein isoforms from a single gene. This increases the complexity and diversity of the proteome.
5.
Eukaryotic mRNA molecules are modified
Correct Answer
C. In the nucleus
Explanation
Eukaryotic mRNA molecules are modified in the nucleus. This is where pre-mRNA undergoes several post-transcriptional modifications, including the addition of a 5' cap and a poly-A tail, as well as the removal of introns through a process called splicing. These modifications are crucial for the stability, transport, and translation of the mRNA molecule. Once the modifications are completed, the mature mRNA is then transported out of the nucleus and into the cytoplasm, where it can be translated into protein on the ribosomes.
6.
Transcription is the first stage of Central Dogma. Transcription is initiated by
Correct Answer
B. RNA polymerase binding to a site known as the promoter
Explanation
RNA polymerase binding to a site known as the promoter is the correct answer because transcription is the process by which RNA is synthesized from a DNA template. This process is initiated when RNA polymerase binds to a specific DNA sequence called the promoter. The promoter region is located upstream of the gene and contains the necessary signals for RNA polymerase to recognize and bind to the DNA. Once bound, RNA polymerase can begin transcribing the DNA into RNA. Therefore, RNA polymerase binding to the promoter is crucial for the initiation of transcription.
7.
If the sequence of bases in a section of template DNa is ATCGCTCC, what is the corresponding sequence of bases in mRNA?
Correct Answer
C. UAGCGAGG
Explanation
The corresponding sequence of bases in mRNA can be determined by replacing each base in the DNA sequence with its complementary base in RNA. In DNA, A (adenine) pairs with T (thymine), C (cytosine) pairs with G (guanine), and vice versa. Therefore, the complementary sequence for ATCGCTCC in RNA would be UAGCGAGG.
8.
The site from where the empty RNA molecules exit the ribosome is the
Correct Answer
A. E site
Explanation
The E site is the site from where the empty RNA molecules exit the ribosome. This site is responsible for releasing the uncharged tRNA after it has delivered its amino acid to the growing polypeptide chain. The E site is one of the three binding sites on the ribosome, along with the A site and P site. The A site is where the incoming aminoacyl-tRNA binds, while the P site is where the tRNA carrying the growing polypeptide chain is located. The active site refers to the specific region of an enzyme where catalysis takes place, while the allosteric site is a different site on the enzyme that can regulate its activity.
9.
All of the following are different componesnts of the protein synthesizing machinery except
Correct Answer
C. DNA polymerase
Explanation
The correct answer is DNA polymerase. DNA polymerase is not a component of the protein synthesizing machinery. mRNA carries the genetic information from DNA to the ribosomes, tRNA brings the amino acids to the ribosomes, ribosomes are the site of protein synthesis, and amino acids are the building blocks of proteins. DNA polymerase, on the other hand, is an enzyme involved in DNA replication and repair, not protein synthesis.
10.
The basic mechanism of gene expression is often referred to as the "central dogma". Which description best fits the Central Dogma?
Correct Answer
E. Information stored in DNA is transferred to an RNA copy and the RNA copy directs the sequential assembly of amino acids.
Explanation
The Central Dogma describes the flow of genetic information in cells. It states that the information stored in DNA is first transferred to an RNA copy through a process called transcription. This RNA copy, known as messenger RNA (mRNA), then directs the sequential assembly of amino acids during a process called translation. This translation process occurs at the ribosomes in the cell and results in the formation of a polypeptide chain, which will fold into a specific three-dimensional shape to become a functional protein. Therefore, the description that best fits the Central Dogma is "Information stored in DNA is transferred to an RNA copy and the RNA copy directs the sequential assembly of amino acids."
11.
The method of DNA replication, where each original strand s used as a template to build a new strand is called the
Correct Answer
B. Semiconservative method
Explanation
The correct answer is the semiconservative method. In this method of DNA replication, each original strand of DNA serves as a template for the synthesis of a new complementary strand. The resulting DNA molecule consists of one original strand and one newly synthesized strand. This process ensures the conservation of one parental DNA strand in each new DNA molecule, hence the term "semiconservative." The other options (conservative method, disruptive method, continuous method, and replication and amplification method) do not accurately describe this process of DNA replication.
12.
The enzyme that catalyzes the synthesis of new DNA molecules is called
Correct Answer
A. DNA polymerase
Explanation
DNA polymerase is the correct answer because it is the enzyme responsible for catalyzing the synthesis of new DNA molecules. DNA polymerase adds nucleotides to the growing DNA strand during DNA replication, ensuring accurate replication of the genetic material. DNA Ligase, RNA polymerase, RNA ligase, and tRNA primase are not involved in the synthesis of new DNA molecules.
13.
When nonvirulent bacteria were mixed with dead virulent bacteria, Griffith unexpectedly found that the injected mice died. He explained ths behavior by suggesting the nonvirulent strain of bacteria had been
Correct Answer
B. Transformed
Explanation
Griffith's unexpected observation of the injected mice dying when nonvirulent bacteria were mixed with dead virulent bacteria suggests that the nonvirulent strain of bacteria had undergone a transformation. This transformation could have potentially caused the nonvirulent bacteria to acquire the ability to cause disease and become virulent.
14.
Hershey-Chase concluded from their experiment with bacteriophage that
Correct Answer
C. DNA is the genetic material
Explanation
Hershey-Chase concluded from their experiment with bacteriophage that DNA is the genetic material. This conclusion was based on their use of radioactive labeling to track the movement of genetic material in the bacteriophage. They found that when the DNA was labeled, it was transferred to the host bacteria, while the protein coat remained outside. This provided strong evidence that DNA, not proteins, carries the genetic information. Therefore, the correct answer is DNA is the genetic material.
15.
DNA primase
Correct Answer
E. Creates a short RNA primer complementary to the DNA template
Explanation
DNA primase is an enzyme responsible for initiating DNA replication. It synthesizes a short RNA primer that is complementary to the DNA template. This RNA primer provides the starting point for DNA polymerase to begin synthesizing new DNA strands during replication.
16.
The chemical bond connecting one nucleotide with the next one along the nucleic acid chain is called a
Correct Answer
D. pHospHodiester bond
Explanation
A phosphodiester bond is the correct answer because it is the chemical bond that connects one nucleotide to the next in a nucleic acid chain. This bond forms between the phosphate group of one nucleotide and the sugar group of the next nucleotide, creating a strong covalent bond. This bond is important for the stability and integrity of the nucleic acid chain, as it forms the backbone of DNA and RNA molecules.
17.
Replication always proceeds by adding new bases to the
Correct Answer
C. 3' end
Explanation
Replication always proceeds by adding new bases to the 3' end. In DNA replication, the enzyme DNA polymerase adds nucleotides to the growing DNA strand in a 5' to 3' direction. The 3' end of the DNA molecule has a free hydroxyl (-OH) group, which allows for the addition of new nucleotides. Therefore, replication occurs in the 3' to 5' direction on the template strand, resulting in the synthesis of a new complementary strand in the 5' to 3' direction.
18.
Fourteen percent of the DNA molecules from a certain organism contain T. What amounts of other bases would you expect to e present in this particular DNA?
Correct Answer
B. 14% A 36% C 36 G
Explanation
The correct answer is 14% A 36% C 36% G. This is because DNA is made up of four bases: adenine (A), cytosine (C), guanine (G), and thymine (T). The question states that 14% of the DNA molecules contain T, so the remaining percentage must be divided among the other three bases. Since T is not mentioned in the answer choices, it can be eliminated. Therefore, the percentages of A, C, and G must add up to 100% minus 14% (the percentage of T), which is 86%. The answer choice that fits this requirement is 14% A, 36% C, and 36% G.
19.
If a short sequence of DNA is AATTGCGCGT, its complement is
Correct Answer
C. TTAACGGCA
Explanation
The given short sequence of DNA is AATTGCGCGT. To find its complement, we need to replace each nucleotide with its complementary base. A is complementary to T, T is complementary to A, G is complementary to C, and C is complementary to G. By applying this rule to the given sequence, we get the complement as TTAACGGCA.
20.
DNA Polymerase III synthesizes the leading strand as a continuous strand. The lagging strands are synthesized in segments called
Correct Answer
D. Okasaki fragments
Explanation
DNA Polymerase III synthesizes the leading strand as a continuous strand, meaning it can replicate the DNA strand in one continuous motion. However, the lagging strand is synthesized in short segments called Okazaki fragments. This is because the DNA double helix is anti-parallel, and DNA polymerase can only add nucleotides in the 5' to 3' direction. As the replication fork moves, the lagging strand is synthesized in the opposite direction, so it must be synthesized in short fragments that are later joined together by DNA ligase.
21.
DNA can be cleaved at a specific site, generating in most cases two fragments with short single-stranded ends. The chemical tool used to cleave the DNA is called
Correct Answer
C. Restriction enzyme
Explanation
Restriction enzymes are chemical tools used to cleave DNA at specific sites, generating two fragments with short single-stranded ends. These enzymes recognize specific DNA sequences and cleave the phosphodiester bonds within the DNA backbone. This cleavage allows for further manipulation of the DNA, such as cloning or analysis. The other options, hybridization enzyme, endonuclease, and complementary enzyme, do not accurately describe the chemical tool used for DNA cleavage.
22.
DNA fragments complementary tothe DNA eing investigated are referred to as
Correct Answer
B. CDNA
Explanation
cDNA stands for complementary DNA. It is synthesized from a messenger RNA (mRNA) template through a process called reverse transcription. This enzyme-based reaction converts the mRNA into a DNA molecule that is complementary to the original mRNA sequence. cDNA is often used in molecular biology research to study gene expression and create gene libraries. It lacks introns and represents the coding regions of genes, making it a valuable tool for cloning and studying specific genes of interest.
23.
The ends of DNA fragments produced by the same restriction enzyme can be joined together by another enzyme,
Correct Answer
D. NA ligase
Explanation
DNA ligase is the correct answer because it is an enzyme that is responsible for joining the ends of DNA fragments together. It catalyzes the formation of phosphodiester bonds between the sugar-phosphate backbones of the DNA strands, sealing the nicks or gaps in the DNA molecule. This process is essential for DNA replication, repair, and recombination. DNA polymerase is responsible for synthesizing new DNA strands, DNA methylase adds methyl groups to DNA, and DNA primase synthesizes RNA primers during DNA replication.
24.
Vehicles of transport for foreign DNA fragments may be viruses or bacterial plasmids. These may be referred as
Correct Answer
A. Vectors
Explanation
Vehicles of transport for foreign DNA fragments are called vectors. These can be viruses or bacterial plasmids that are used to introduce the foreign DNA into a host organism. Vectors are commonly used in genetic engineering and biotechnology to manipulate and transfer genetic material. They act as carriers, delivering the foreign DNA into the host organism's cells, where it can be expressed and studied.
25.
The polymerase chain reaction, more popularly known as PCR, is a multistep process critical to many research and forensic applications. The process includes all of the following steps EXCEPT
Correct Answer
B. Treatment of new fragments with ligase
Explanation
The correct answer is treatment of new fragments with ligase. The polymerase chain reaction (PCR) is a method used to amplify a specific DNA sequence. The steps of PCR include denaturation, where the DNA is heated to separate the strands, annealing, where primers bind to the complementary sequences on the DNA, and primer extension, where DNA polymerase adds nucleotides to extend the DNA strand. However, treatment of new fragments with ligase is not a step in PCR. Ligase is an enzyme that joins DNA fragments together, but in PCR, the amplification is achieved through the use of primers and DNA polymerase, not ligase.
26.
When electical current is applied during a gel electrophoresis procedure, the DNA fragments are separated on the basis of
Correct Answer
D. The size of the fragments
Explanation
During a gel electrophoresis procedure, electrical current is applied to separate DNA fragments based on their size. The smaller fragments move faster through the gel matrix, while larger fragments move slower. This is because the smaller fragments experience less resistance from the gel matrix and can navigate through the pores more easily. Therefore, the size of the fragments is the determining factor for their separation during gel electrophoresis.
27.
A commercially significant human protein can now produced in bacteria s
Correct Answer
D. Human insulin
Explanation
Human insulin is the correct answer because it is a commercially significant human protein that can now be produced in bacteria. This development has revolutionized the production of insulin for diabetes treatment, as it eliminates the need for animal-based insulin sources and allows for large-scale production at a lower cost. Bacteria, such as E. coli, are genetically modified to produce human insulin, which is then purified and used for medical purposes. This advancement has greatly improved the accessibility and affordability of insulin for patients worldwide.
28.
By examining and comparing several loci between two genomes, and carefully considering how common or rare the characteristics of the loci are, scientists can distinguish between DNA of different individuals, thus making the information useful in criminal investigations. The technique used is called
Correct Answer
A. Restriction fragment length polymorpHisms
Explanation
By examining and comparing several loci between two genomes, scientists can identify differences in the lengths of restriction fragments, which are specific DNA sequences. These variations, known as restriction fragment length polymorphisms (RFLPs), can help distinguish between DNA samples from different individuals. RFLP analysis is a technique commonly used in criminal investigations to match DNA evidence to potential suspects or exclude individuals from being involved in a crime. This method involves digesting DNA samples with restriction enzymes, separating the resulting fragments using gel electrophoresis, and then analyzing the fragment patterns to determine genetic differences.
29.
Goals of genetic engineering for plants include all of the following EXCEPT:
Correct Answer
D. Eliminate genetic variability in crop plants
Explanation
The goals of genetic engineering for plants include producing plants that are resistant to diseases, nutritionally superior, capable of nitrogen fixation, and have an extended shelf life after being harvested. However, eliminating genetic variability in crop plants is not one of the goals of genetic engineering. Genetic variability is important for crop plants as it allows for adaptation to different environmental conditions and helps in maintaining genetic diversity within the plant population.
30.
Medical applications of genetic biotechnology that are currently accepted and underway include all of the following EXCEPT:
Correct Answer
B. Reproductive cloning of humans
Explanation
The correct answer is reproductive cloning of humans. Reproductive cloning involves creating an identical copy of an existing individual, which raises ethical concerns and is currently not accepted in medical applications. Other medical applications of genetic biotechnology include the development of safe vaccines, replacement cloning of humans (creating new organs or tissues for transplantation), replacement of defective genes in disease sufferers, and construction of recombinants for the production of specific antibodies.
31.
A Diploid organism that has two identical alleles for the same trait is called _______ for that particular trait.
Correct Answer
A. Homozygous
Explanation
A diploid organism that has two identical alleles for the same trait is called homozygous for that particular trait. This means that both alleles for the trait are the same, whether they are dominant or recessive. Homozygosity can occur for dominant traits (when both alleles are dominant) or recessive traits (when both alleles are recessive). In either case, the organism will display the trait determined by those alleles.
32.
An allele that is present but unexpressed is
Correct Answer
E. Recessive
Explanation
An allele that is present but unexpressed is considered recessive because it does not have a visible effect on the phenotype when paired with a dominant allele. In order for a recessive allele to be expressed, an individual must inherit two copies of the recessive allele.
33.
In a heterozygous individual the allele being expressed is
Correct Answer
D. Dominant
Explanation
In a heterozygous individual, the dominant allele is the one that is expressed. This means that even though there are two different alleles present, the dominant allele "dominates" over the recessive allele and determines the phenotype of the individual. The recessive allele is present but is not expressed in the phenotype.
34.
The allelic make up of an individual is referred to as its
Correct Answer
B. Genotype
Explanation
The allelic make up of an individual refers to the combination of alleles present in their genes. This combination determines the individual's genotype, which is the genetic information they inherit from their parents. The genotype influences the individual's traits and characteristics, known as their phenotype. Therefore, the correct answer is genotype.
35.
Let P= purple flowers and p= white, and T= tall and t = dwarf. What would be the appearance of a plant with the genotype ppTt?
Correct Answer
C. White flowers, tall
Explanation
The genotype ppTt indicates that the plant has two recessive alleles for flower color (pp) and one dominant allele for height (Tt). Since the dominant allele for flower color (P) is absent, the plant will have white flowers. However, since the dominant allele for height (T) is present, the plant will be tall. Therefore, the appearance of a plant with the genotype ppTt would be white flowers, tall.
36.
If two pure-breeding parents produce offspring who may appear to have blended or diluted phenotypes, a possible explanation is that this train is an example of
Correct Answer
A. Incomplete dominance
Explanation
If two pure-breeding parents produce offspring who may appear to have blended or diluted phenotypes, a possible explanation is incomplete dominance. Incomplete dominance occurs when neither allele is completely dominant over the other, resulting in a phenotype that is a blend of both alleles. In this case, the offspring may have a phenotype that is intermediate between the phenotypes of the two parents, indicating incomplete dominance.
37.
Sometimes one gene pair will interact so as to control the expression of a second gene pair in an interaction called
Correct Answer
E. Epistasis
Explanation
Epistasis is the correct answer because it refers to the interaction between different gene pairs, where one gene pair controls the expression of another gene pair. This interaction can result in the masking or altering of the phenotypic effects of the second gene pair. Epistasis is a form of gene regulation where the expression of one gene is dependent on the presence or activity of another gene. It can occur in various ways, such as dominant epistasis or recessive epistasis, and is an important factor in determining the inheritance patterns of certain traits.
38.
If an individual allele has more than one effect on the phenotype it is said to be
Correct Answer
A. Pleiotropic
Explanation
Pleiotropy refers to a situation where a single gene or allele has multiple effects on the phenotype. This means that the allele can influence multiple traits or characteristics of an organism. In other words, it has a broad impact on the phenotype beyond just one specific trait. This can occur when a gene is involved in multiple biochemical pathways or when it affects the development of different tissues or organs. Pleiotropy is a common phenomenon in genetics and can have significant implications for understanding the complexity of traits and diseases.
39.
Children born in areas where proper nutrition is not available to them do not always realize their full growth potential. These children have the genes for normal growth of bones. Which of the following statements can best explain this situation?
Correct Answer
B. Since nutrition is necessary for proper development and is a part of the environment, it is a clear case of environmental effect on the pHenotype
Explanation
The correct answer is "Since nutrition is necessary for proper development and is a part of the environment, it is a clear case of environmental effect on the phenotype." This statement explains that the lack of proper nutrition affects the development of children and their ability to reach their full growth potential. Nutrition is an environmental factor that directly impacts the phenotype, which refers to the observable characteristics of an individual. Therefore, the statement correctly explains the situation described in the question.
40.
A man whose blood type is AB and a woman blood type is A conceive a child. The woman's mother (the child's maternal grandmother) was type O. The child could not be expected to have a blood type that is
Correct Answer
A. O
Explanation
Since the mother's blood type is A and the father's blood type is AB, the child could inherit either an A or B blood type from the father. However, since the child's maternal grandmother has a blood type of O, it means that the mother carries an O allele. Therefore, the child could not have a blood type of O, as both parents would need to pass on an O allele for the child to have blood type O.
41.
As an anmal matures, it forms attachments to other individuals and develops lasting preferences. This process is called
Correct Answer
B. Imprinting
Explanation
As an animal matures, it forms attachments to other individuals and develops lasting preferences. This process is called imprinting. Imprinting refers to the formation of strong and long-lasting bonds between an animal and its caregiver or other individuals during a critical period of development. It is a form of learning that occurs early in an animal's life and influences their behavior and social interactions throughout their lifetime.
42.
The processing of information and response in a manner that suggests thinking in the animal is called
Correct Answer
E. Cognitive behavior
Explanation
Cognitive behavior refers to the processing of information and response in a manner that suggests thinking in animals. This behavior involves mental processes such as perception, memory, learning, problem-solving, and decision-making. It indicates that animals are capable of higher-level cognitive abilities and can adapt their behavior based on their understanding of the environment and their own internal states.
43.
Ultimate causation dictates that an organism must obtain nutrients to maintain metabolism and promote reproduction. However, the act of killing prey and eating it to avoid the discomfort of hunger pangs is considered an example of
Correct Answer
D. Proximal causation
Explanation
Proximal causation refers to the immediate cause or mechanism that leads to a specific behavior or action. In this case, the act of killing prey and eating it to avoid hunger pangs is an example of proximal causation because it directly addresses the immediate need for nutrients to maintain metabolism and avoid discomfort. The other options, such as animal nerve networks, animal phylogeny, animal internal state, and altruism, do not specifically address the immediate cause and mechanism of this behavior.
44.
If an unrelated stimulus, such as the ringing of a bell was represented at the same time as the food, over repeated trials, a dog would salivate in response to the sound of the bell alone. This kind of response is called
Correct Answer
B. Classical conditioning
Explanation
Classical conditioning is the correct answer because it refers to a type of learning where an organism learns to associate a neutral stimulus with a stimulus that naturally elicits a response. In the given scenario, the ringing of a bell (neutral stimulus) is repeatedly paired with the presentation of food (stimulus that naturally elicits salivation). As a result, the dog eventually learns to associate the sound of the bell with the arrival of food and starts salivating in response to the bell alone, even without the presence of food. This process demonstrates classical conditioning.
45.
An animal learns to associate its behavioral response with a reward or punishment in
Correct Answer
C. Operant conditioning
Explanation
Operant conditioning is a type of learning in which an animal associates its behavioral response with a reward or punishment. In operant conditioning, the animal learns to repeat behaviors that are followed by a reward and avoid behaviors that are followed by a punishment. This type of learning is different from classical conditioning, which involves associating a neutral stimulus with a natural response. Imprinting, on the other hand, refers to a rapid learning process in which an animal forms an attachment to a particular object or individual shortly after birth.
46.
A behavior that has evolved to aid relatives, although at personal rink, and thus increases the chance of your genes being passed on to the next generation is known as
Correct Answer
C. Kin selection
Explanation
Kin selection is the correct answer because it refers to a behavior that has evolved to aid relatives, even at personal risk. This behavior increases the chances of an individual's genes being passed on to the next generation. Kin selection is a concept in evolutionary biology that explains the apparent selflessness of individuals towards their relatives, as they share a portion of their genetic makeup. This behavior enhances the survival and reproductive success of related individuals, ultimately benefiting the individual's own genetic legacy.
47.
An organism can increase its inclusive fitness by directly propagating its alleles through its own reproduction and through
Correct Answer
C. Behaviors that benefit relatives likely to share some of the same genes
Explanation
An organism can increase its inclusive fitness by engaging in behaviors that benefit its relatives who are likely to share some of the same genes. This is because by helping their relatives, they indirectly propagate their own alleles and increase the chances of those alleles being passed on to future generations. This behavior is known as kin selection and is a mechanism for increasing inclusive fitness. By assisting their relatives, organisms can enhance the survival and reproductive success of individuals who carry similar genetic material, thus indirectly promoting the spread of their own genes in the population.
48.
Chemical messengers used for communication between animal species are called
Correct Answer
B. pHeromones
Explanation
Pheromones are chemical messengers used for communication between animal species. They are released into the environment and can be detected by other individuals of the same species, influencing their behavior or physiology. Pheromones play a crucial role in various social and reproductive behaviors, such as attracting mates, marking territories, or warning of danger. Hormones, on the other hand, are chemical messengers that regulate physiological processes within an individual's body. While hormones can also have effects on behavior, they primarily act within the same individual rather than between different species.
49.
Young birds see objects flying overhead and respond by crouching down into the nest and remaining still. Over time objects become familiar and the young birds do not crouch down. This type of learning is referred to as
Correct Answer
D. Habituation
Explanation
Habituation is the correct answer because it refers to the process by which an organism gradually becomes less responsive to a repeated or irrelevant stimulus. In this case, the young birds initially respond to objects flying overhead by crouching down into the nest and remaining still. However, as they are repeatedly exposed to these objects and realize that they are not a threat, they become familiar with them and no longer feel the need to crouch down. This change in behavior is a result of habituation.
50.
In species where the young are precocial, meaning requiring little parental care, males may be more likely to
Correct Answer
D. Seek to mate with many females in a single breeding season
Explanation
In species where the young are precocial and require little parental care, males are more likely to seek to mate with many females in a single breeding season. This is because they do not need to invest as much time and energy in caring for the offspring. Instead, they can maximize their reproductive success by mating with multiple females, increasing their chances of passing on their genes. This strategy allows them to spread their genetic material widely and increase their chances of producing offspring.