1.
Which of the following is not an example of a scientific model?
Correct Answer
D. A data table from a plant-growth experiment
Explanation
A data table from a plant-growth experiment is not an example of a scientific model because it is a representation of collected data rather than a visual or conceptual representation of a scientific phenomenon or process. Scientific models are typically used to explain, predict, or understand natural phenomena, while a data table simply presents the results of an experiment.
2.
Which of the following is the best example of biodiversity?
Correct Answer
D. There are over a million different species in the jungles of Africa.
Explanation
The best example of biodiversity is the presence of over a million different species in the jungles of Africa. Biodiversity refers to the variety of life forms in a particular ecosystem or on the entire planet. The presence of a large number of different species indicates a high level of biodiversity, which is important for the stability and health of an ecosystem.
3.
___ is the process of maintaining proper internal conditions such as water balance, blood sugar levels, and pH.
Correct Answer
A. Homeostasis
Explanation
Homeostasis is the process of maintaining proper internal conditions such as water balance, blood sugar levels, and pH. It is a regulatory mechanism that allows organisms to maintain a stable and balanced internal environment despite external changes. Through various physiological processes, homeostasis ensures that the body's internal conditions remain within a narrow range, which is necessary for the proper functioning of cells and overall health. This process involves feedback loops and adjustments made by various organ systems to maintain equilibrium. Protein synthesis, biodiversity, and adaptation are not directly related to the maintenance of internal conditions and are therefore not the correct answers.
4.
Finch species in the Galapagos Islands have a wide variety of beak shapes. The theory of natural selection suggests that these differences arose because
Correct Answer
B. The birds on different islands have different food sources.
Explanation
The correct answer is that the birds on different islands have different food sources. This is because the theory of natural selection suggests that organisms with advantageous traits for their specific environment are more likely to survive and reproduce. In the case of the finch species in the Galapagos Islands, the different beak shapes have evolved to be better suited for accessing and consuming the specific types of food available on each island. This variation in food sources has led to the development of different beak shapes among the finch species.
5.
A scientist wants to know how a certain fertilizer affects the growth of tomato plants growing in two different soils. What conclusion can be drawn from the graph shown here?
Correct Answer
C. The fertilizer has a greater effect in Soil 2
Explanation
The graph shows that the tomato plants in Soil 2 had a significantly higher growth rate compared to the plants in Soil 1 when the fertilizer was applied. This suggests that the fertilizer had a greater effect on the growth of tomato plants in Soil 2.
6.
Which of the following groups is most important for bringing energy into an ecosystem?
Correct Answer
B. Producers
Explanation
Producers are the most important group for bringing energy into an ecosystem. They are able to convert sunlight into usable energy through the process of photosynthesis. This energy is then transferred to other organisms in the ecosystem through the food chain. Without producers, there would be no source of energy for the rest of the ecosystem, and all other organisms would eventually die off. Therefore, producers play a crucial role in sustaining the energy flow and overall functioning of an ecosystem.
7.
What would most likely result if nitrogen-fixing bacteria in an area were destroyed?
Correct Answer
B. Vegetation in the area would grow at a slower rate.
Explanation
Nitrogen-fixing bacteria play a crucial role in the nitrogen cycle by converting atmospheric nitrogen into a usable form for plants. If these bacteria were destroyed, the availability of nitrogen for plants would decrease significantly. Nitrogen is an essential nutrient for plant growth and development, as it is a component of proteins, nucleic acids, and chlorophyll. Without an adequate supply of nitrogen, plants would struggle to produce these essential molecules, resulting in slower growth rates. Therefore, the destruction of nitrogen-fixing bacteria would most likely lead to a slower growth rate of vegetation in the area.
8.
A scientist wants to measure the size of a cactus population in a desert valley. What method should she use?
Correct Answer
C. Quadrat sampling
Explanation
To measure the size of a cactus population in a desert valley, the scientist should use quadrat sampling. This method involves dividing the study area into smaller sections using quadrats, which are square frames. The scientist can then count the number of cacti within each quadrat to estimate the population size. This method is effective for studying stationary or sessile organisms, such as cacti, and provides a systematic and unbiased approach to population estimation. Radio telemetry is used for tracking the movement of animals, mark-recapture sampling is used for mobile organisms, and computer modeling is a simulation-based approach that may not be as accurate as direct sampling in this case.
9.
In which direction does energy flow through this energy pyramid?
Correct Answer
A. 1,2,3,4
Explanation
The energy flows from the bottom to the top of the energy pyramid. In an energy pyramid, each level represents a trophic level, with producers at the bottom and consumers at higher levels. The producers, such as plants, capture energy from the sun and convert it into food energy through photosynthesis. This energy is then passed on to the primary consumers, which are herbivores that eat the plants. The primary consumers are then consumed by secondary consumers, and so on. Therefore, the correct answer indicates that energy flows from level 1 (producers) to level 2 (primary consumers), then to level 3 (secondary consumers), and finally to level 4 (tertiary consumers).
10.
In the carbon cycle, through what process does carbon move from an abiotic resource into organic matter?
Correct Answer
A. Combustion
Explanation
Combustion is the process through which carbon moves from an abiotic resource, such as fossil fuels, into organic matter. During combustion, carbon-containing substances are burned, releasing carbon dioxide into the atmosphere. This carbon dioxide can then be absorbed by plants during photosynthesis, converting it into organic matter. Therefore, combustion plays a crucial role in transferring carbon from non-living sources to living organisms in the carbon cycle.
11.
This food web shows the relationships between organisms in an ecosystem. Which type of organism not shown in this food web is important to the stability of the ecosystem?
Correct Answer
A. Decomposer
Explanation
Decomposers are organisms that break down dead organic matter, such as dead plants and animals, into simpler substances. They play a crucial role in the ecosystem by recycling nutrients back into the environment, making them available for other organisms to use. Without decomposers, dead organic matter would accumulate and nutrients would become locked away, disrupting the nutrient cycle and affecting the stability of the ecosystem. Therefore, decomposers are important for maintaining the balance and stability of the ecosystem, even though they are not directly shown in the food web.
12.
In many parts of the United States, native plants that once grew on the forest floor have been replaced by garlic mustard, an invasive species that thrives in cool forest understories. This situation is an example of ___.
Correct Answer
D. Competition between species.
Explanation
The given situation describes a scenario where native plants are being replaced by garlic mustard, an invasive species. This indicates that both the native plants and garlic mustard are competing for the same resources, such as space, nutrients, and sunlight, in the forest understory. This competition between the native plants and garlic mustard for limited resources is the reason for the shift in plant composition, making "competition between species" the correct answer.
13.
Archaeologists find that the disappearance of a large mammal occurred shortly after the arrival of hominids in a certain area. What most likely occurred between these two species?
Correct Answer
B. Predation
Explanation
The most likely occurrence between hominids and the large mammal is predation. This means that the hominids likely hunted and killed the large mammal for food or other resources. The disappearance of the large mammal shortly after the arrival of the hominids suggests a possible relationship between the two species where the hominids hunted and preyed upon the large mammal, leading to its disappearance.
14.
What is the function of autotrophs in the carbon cycle?
Correct Answer
C. To use carbon dioxide to produce glucose
Explanation
Autotrophs play a crucial role in the carbon cycle by using carbon dioxide to produce glucose through the process of photosynthesis. This process helps remove carbon dioxide from the atmosphere and convert it into organic compounds, which are then used as a source of energy by autotrophs and other organisms in the food chain. By doing so, autotrophs contribute to the balance of carbon in the environment and the availability of nutrients for other organisms.
15.
Which of these best completes the concept map?
Correct Answer
A. Extreme drought
Explanation
Extreme drought completes the concept map because it is a natural phenomenon that can have severe consequences on the environment and human life. It is characterized by a prolonged period of significantly below-average rainfall, leading to water scarcity, crop failure, and ecosystem disruption. Extreme drought is closely related to pollution and acid rain as they can exacerbate its effects. An earthquake, although a natural disaster, does not directly relate to the concept of extreme drought.
16.
A student constructs several terrariums like the one shown. Each terrarium is exposed to a different amount of sunlight each day. In order to determine the ideal amount of sunlight, which of the following variables must be held constant?
Correct Answer
A. Types of plants
Explanation
To determine the ideal amount of sunlight for the terrariums, the student needs to hold the variable of "types of plants" constant. This is because different types of plants have different sunlight requirements. By keeping the types of plants consistent, the student can accurately assess the effect of varying amounts of sunlight on plant growth.
17.
Bacteria adapt more quickly to environmental changes than elephants. Which best explains this difference?
Correct Answer
B. Bacteria reproduce more rapidly
Explanation
Bacteria reproduce more rapidly than elephants, which allows them to adapt more quickly to environmental changes. This is because bacteria have shorter generation times and can produce a large number of offspring in a short period of time. This rapid reproduction increases the chances of genetic variation and allows for the selection of beneficial traits that help the bacteria survive in changing environments. Elephants, on the other hand, have longer generation times and produce fewer offspring, making it harder for them to adapt quickly to environmental changes.
18.
The structures labeled B are called ___.
Correct Answer
B. Fatty acids
Explanation
The structures labeled B are called fatty acids. Fatty acids are long chains of hydrocarbons with a carboxyl group at one end. They are an important component of lipids, which are essential for energy storage, insulation, and cell membrane structure. Fatty acids can be saturated (no double bonds) or unsaturated (one or more double bonds). They play a crucial role in various metabolic processes and are obtained through the diet or synthesized by the body.
19.
The ___ form of this molecule is found in animals and is ___ at room temperature.
Correct Answer
A. Saturated… solid
Explanation
The correct answer is saturated... solid. In organic chemistry, the term "saturated" refers to a molecule that contains only single bonds between carbon atoms and is fully saturated with hydrogen atoms. Saturated fats, for example, are solid at room temperature and are commonly found in animal products such as meat and dairy. This is because the straight chains of saturated fatty acids can pack closely together, resulting in a solid state.
20.
If you ate bacon and fried eggs for breakfast, the largest component of the energy would come from the ___.
Correct Answer
D. Lipids
Explanation
Lipids, also known as fats, are the largest component of energy in bacon and fried eggs. Lipids are a concentrated source of energy, providing more calories per gram compared to carbohydrates and proteins. Therefore, consuming bacon and fried eggs for breakfast would primarily derive its energy from lipids.
21.
Organic compounds ALL contain the element carbon. Which organic compound, used for stored chemical energy, contains carbon, hydrogen, oxygen, and often phosphorous?
Correct Answer
B. Lipids
Explanation
Lipids are organic compounds that contain carbon, hydrogen, and oxygen, and often phosphorous. They are used for stored chemical energy in the body. Therefore, lipids are the correct answer to the question.
22.
Water (H2O) is an example of a molecule whose atoms are held together by which of the following?
Correct Answer
B. Covalent bonds
Explanation
Water (H2O) is an example of a molecule whose atoms are held together by covalent bonds. Covalent bonds occur when atoms share electrons, resulting in a stable molecule. In the case of water, the oxygen atom shares its electrons with two hydrogen atoms, forming a covalent bond. This sharing of electrons allows the water molecule to have a bent shape and gives it unique properties such as polarity, which is responsible for its ability to dissolve many substances.
23.
The specific chemical that an enzyme will act on is called a(n)___.
Correct Answer
C. Substrate
Explanation
An enzyme is a protein that acts as a catalyst, speeding up chemical reactions in the body. The specific chemical that an enzyme acts on is called a substrate. Enzymes have a specific shape that allows them to bind to their substrate and facilitate the conversion of the substrate into a product. Therefore, the correct answer is substrate.
24.
A bond that is formed when two atoms share electrons is called a ___.
Correct Answer
A. Covalent bond
Explanation
A covalent bond is formed when two atoms share electrons. In this type of bond, the electrons are shared between the atoms rather than being transferred from one atom to another. This sharing of electrons allows the atoms to achieve a stable electron configuration and form a strong bond. Covalent bonds are typically found between nonmetals or between a nonmetal and a metalloid.
25.
The picture at the right is an example of a(n) ___.
Correct Answer
C. Atomic model
Explanation
The given picture is an example of an atomic model. Atomic models are representations of atoms that help us understand their structure and behavior. They show the arrangement of protons, neutrons, and electrons within an atom. These models are important in studying and explaining various atomic properties and phenomena.
26.
Gametes must be haploid because ___.
Correct Answer
C. Two gametes will unite during fertilization to create a diploid cell
Explanation
Gametes must be haploid because when two gametes unite during fertilization, they combine their genetic material to create a diploid zygote. If the gametes were not haploid, the resulting zygote would have double the number of chromosomes, leading to an abnormal number of chromosomes in the offspring. Therefore, gametes need to be haploid to ensure the proper number of chromosomes in the offspring.
27.
What ratio of the offspring from the cross shown will be homozygous recessive for the trait of tallness?
Correct Answer
A. 0 in 4
Explanation
The correct answer is 0 in 4 because the question is asking for the ratio of offspring that will be homozygous recessive for the trait of tallness. If the answer is 0 in 4, it means that none of the offspring will have the homozygous recessive genotype for tallness.
28.
What is the probability that a heterozygous black-fur rabbit will produce white-fur offspring if its mate is a homozygous recessive rabbit?
Correct Answer
B. P = 1/2
Explanation
When a heterozygous black-fur rabbit mates with a homozygous recessive rabbit, there is a 50% chance that the offspring will inherit the recessive white-fur allele from the homozygous recessive parent. This is because the heterozygous black-fur rabbit carries both the dominant black-fur allele and the recessive white-fur allele, while the homozygous recessive rabbit only carries the recessive white-fur allele. Therefore, there is an equal chance for the offspring to receive either the dominant black-fur allele or the recessive white-fur allele, resulting in a probability of 1/2 or 50% for the offspring to have white fur.
29.
The picture shows a student’s experiment with a common aquatic plant. Which change in this experiment is most likely to increase the volume of oxygen gas that accumulates in the top of the tube?
Correct Answer
C. Move the light source closer to the beaker
Explanation
Moving the light source closer to the beaker is most likely to increase the volume of oxygen gas that accumulates in the top of the tube. This is because aquatic plants undergo photosynthesis, a process that requires light energy to convert carbon dioxide and water into oxygen and glucose. By moving the light source closer to the beaker, the plants will receive more light energy, which will increase their rate of photosynthesis. As a result, more oxygen gas will be produced and accumulate in the top of the tube.
30.
Both male and female rats have genotype Bb. Based on a Punnett square, Carol concluded that the phenotypic ratio of the monohybrid cross is 2:1:1. What mistake did Carol make?
Correct Answer
C. The ratio should be 3:1
Explanation
Carol made the mistake of assuming a 2:1:1 phenotypic ratio based on the genotype Bb. However, the correct phenotypic ratio for a monohybrid cross with genotype Bb is 3:1, with three offspring displaying the dominant phenotype and one offspring displaying the recessive phenotype.
31.
In which phase of meiosis would certain gene segments of the homologous pairs of chromosomes "cross over" and exchange genetic information?
Correct Answer
C. PropHase I
Explanation
During Prophase I of meiosis, homologous pairs of chromosomes come together and align side by side. This close proximity allows for the exchange of genetic information between the chromosomes through a process called crossing over. This crossing over results in the exchange of gene segments between the homologous pairs, increasing genetic diversity. Therefore, Prophase I is the phase of meiosis where certain gene segments of the homologous pairs of chromosomes "cross over" and exchange genetic information.
32.
All the individuals of a species that live in a particular area are called a ___.
Correct Answer
A. Population
Explanation
A population refers to all the individuals of a particular species that live in a specific area. It is a term used in ecology to describe the collective group of organisms of the same species within a defined geographic location. The population of a species can vary in size, density, and distribution, and it plays a crucial role in understanding the dynamics and interactions within an ecosystem. Therefore, in the given question, the correct answer is "population."
33.
The total permanent disappearance of a species from Earth is called ___.
Correct Answer
A. Extinction
Explanation
Extinction refers to the complete and permanent disappearance of a species from Earth. It occurs when there are no remaining individuals of the species alive. This can happen due to various reasons such as habitat destruction, climate change, overhunting, or natural disasters. Extinction is a natural process, but human activities have accelerated the rate of extinction significantly in recent times.
34.
What is the term for a molecule that combines with enzymes, undergoes a chemical reaction, and changes into new substances?
Correct Answer
A. Substrate
Explanation
A substrate is the term used to describe a molecule that combines with enzymes, undergoes a chemical reaction, and changes into new substances. Enzymes are proteins that act as catalysts in biochemical reactions, and they bind to specific substrates to facilitate the conversion of these substrates into different products. Therefore, the correct answer is substrate.
35.
DNA is composed of nucleotide subunits, each of which contains a ___.
Correct Answer
B. pHospHate group
Explanation
DNA is composed of nucleotide subunits, each of which contains a phosphate group. This phosphate group is an essential component of the nucleotide structure, along with a sugar molecule (deoxyribose in DNA) and a nitrogenous base (adenine, thymine, cytosine, or guanine). The phosphate group forms the backbone of the DNA molecule, linking the nucleotides together through phosphodiester bonds. This arrangement of nucleotides and phosphate groups forms the double helix structure of DNA, which is responsible for its stability and ability to store genetic information.
36.
Which process produces the greatest amount of ATP?
Correct Answer
A. Aerobic respiration
Explanation
Aerobic respiration produces the greatest amount of ATP. During aerobic respiration, glucose is broken down in the presence of oxygen to produce carbon dioxide, water, and a large amount of ATP. This process occurs in the mitochondria of cells and is the most efficient way to generate ATP. Fermentation and anaerobic respiration also produce ATP, but in much smaller quantities. Photosynthesis, on the other hand, is the process by which plants convert sunlight into glucose, but it does not directly produce ATP.
37.
In the ladder-like model of DNA, the vertical “backbones” consist of ___.
Correct Answer
D. Sugar and pHospHate groups
Explanation
The ladder-like model of DNA consists of two vertical "backbones" that are made up of sugar and phosphate groups. These sugar and phosphate groups alternate along the length of the DNA molecule, forming the backbone structure. The nitrogen bases are attached to these sugar molecules, forming the rungs of the DNA ladder. ATP, although an important molecule for energy transfer in cells, is not a component of the DNA molecule. Therefore, the correct answer is sugar and phosphate groups.