1.
These organisms often have both a polyp form and a medusa form in their life cycle.
Correct Answer
D. Cnidarians
Explanation
Cnidarians often have both a polyp form and a medusa form in their life cycle. This is a characteristic feature of cnidarians, which include jellyfish, sea anemones, and corals. The polyp form is usually sessile and attached to a substrate, while the medusa form is free-swimming. This life cycle allows cnidarians to adapt to different environments and maximize their chances of survival and reproduction.
2.
These organisms have pharyngeal gill slits and a dorsal hollow nerve cord at some time in their development.
Correct Answer
E. Chordates
Explanation
Chordates are the only organisms among the options that possess both pharyngeal gill slits and a dorsal hollow nerve cord at some point in their development. Echinoderms, annelids, arthropods, and cnidarians do not have these specific characteristics. Chordates, which include vertebrates like fish, amphibians, reptiles, birds, and mammals, exhibit these features during their embryonic stage, indicating their evolutionary relationship to other chordates.
3.
These organisms have radial symmetry and a water vascular system and are generally bottom-dwellers.
Correct Answer
A. Echinoderms
Explanation
Echinoderms are organisms that have radial symmetry and a water vascular system. They are generally bottom-dwellers, meaning they live on the ocean floor. Echinoderms include animals like starfish, sea urchins, and sea cucumbers. Their radial symmetry means that their body parts are arranged around a central axis, similar to the spokes of a wheel. The water vascular system is a network of fluid-filled tubes that helps with movement, feeding, and respiration. Overall, the characteristics described in the question align with the characteristics of echinoderms.
4.
These organisms have a chitinous exoskeleton and jointed appendages.
Correct Answer
C. Arthropods
Explanation
Arthropods are the correct answer because they are characterized by having a chitinous exoskeleton and jointed appendages. This unique combination of features allows arthropods to have a strong and protective outer covering, as well as flexible and versatile limbs for movement and manipulation. Echinoderms, annelids, cnidarians, and chordates do not possess these specific traits, making arthropods the only suitable option.
5.
An animal with anterior, posterior, dorsal, and ventral surfaces on its body must exhibit
Correct Answer
E. Bilateral symmetry.
Explanation
An animal with anterior, posterior, dorsal, and ventral surfaces on its body must exhibit bilateral symmetry. Bilateral symmetry means that the animal's body can be divided into two equal halves along a single plane. This allows for the development of distinct anterior (head) and posterior (tail) ends, as well as dorsal (back) and ventral (belly) surfaces. In contrast, radial symmetry would result in multiple planes of symmetry and a lack of distinct head and tail ends. Protostomic and coelomate development are not directly related to the presence of these body surfaces. Segmentation refers to the division of an animal's body into repeating units and is not necessarily tied to the presence of specific surfaces.
6.
Which of the following groups contains prokaryotic organisms capable of surviving the greatest extremes in temperature or salt concentration?
Correct Answer
B. Archaeabacteria
Explanation
Archaeabacteria are prokaryotic organisms that are known for their ability to survive in extreme conditions such as high temperatures and high salt concentrations. They are often found in environments such as hot springs, deep-sea hydrothermal vents, and salt flats. These organisms have unique adaptations that allow them to thrive in these harsh conditions, such as specialized enzymes and cell membranes. Therefore, the group Archaeabacteria contains prokaryotic organisms capable of surviving the greatest extremes in temperature or salt concentration.
7.
Which of the following groups is best characterized as being eukaryotic and heterotrophic and having chitinous cell walls?
Correct Answer
C. Fungi
Explanation
Fungi is the correct answer because it is a group that is eukaryotic and heterotrophic, meaning they obtain their nutrients by consuming organic matter. Fungi also have chitinous cell walls, which provide structural support and protection. Plantae, Animalia, Viruses, and Archaeabacteria do not possess chitinous cell walls, making Fungi the only group that fits all the given characteristics.
8.
In which of the following pairs are the organisms most closely related taxonomically?
Correct Answer
B. Spider...crayfish
Explanation
The organisms in the pair spider and crayfish are most closely related taxonomically because they both belong to the same phylum, Arthropoda. Arthropods are characterized by having jointed legs and a hard exoskeleton. Both spiders and crayfish are arthropods, although they belong to different classes (Arachnida and Malacostraca, respectively). The other pairs of organisms listed in the question do not share the same phylum or a closer taxonomic relationship.
9.
Bilaterally symmetrical; deuterostome development; dorsal hollow nerve cord
Correct Answer
E. Chordata
Explanation
Chordata is the correct answer because it is the only phylum listed that possesses all three characteristics mentioned: bilaterally symmetrical, deuterostome development, and a dorsal hollow nerve cord. Annelida, Mollusca, Arthropoda, and Echinodermata do not exhibit all three of these characteristics, making them incorrect choices.
10.
Coelomate, exoskeleton; jointed appendages
Correct Answer
C. Arthropoda
Explanation
Arthropoda is the correct answer because it is the only phylum in the given options that possesses both an exoskeleton and jointed appendages. Annelida, Mollusca, Echinodermata, and Chordata do not have an exoskeleton or jointed appendages. Arthropods, such as insects, spiders, and crustaceans, have a hard outer covering (exoskeleton) made of chitin and their limbs are jointed, allowing for flexibility and movement.
11.
Pharyngeal slits; endoskeleton derived from mesoderm; ventral heart
Correct Answer
E. Chordata
Explanation
The presence of pharyngeal slits, an endoskeleton derived from mesoderm, and a ventral heart are all characteristic features of the phylum Chordata. Pharyngeal slits are found in the early embryonic stage of chordates and are used for filter feeding or respiration in some species. The endoskeleton derived from mesoderm provides structural support and protection for the body. The presence of a ventral heart is a unique characteristic of chordates, as most other animals have a dorsal heart. Therefore, based on these features, the correct answer is Chordata.
12.
Internal skeleton; deuterostome development; water-vascular system
Correct Answer
D. Echinodermata
Explanation
Echinoderms have an internal skeleton, undergo deuterostome development, and possess a water-vascular system. The other options, Annelida, Mollusca, Arthropoda, and Chordata, do not possess all of these characteristics. Annelida and Mollusca have a hydrostatic skeleton, Arthropoda have an exoskeleton, and Chordata have a vertebrate endoskeleton. Therefore, the correct answer is Echinodermata.
13.
Closed circulatory system; protostome development; many body segments
Correct Answer
A. Annelida
Explanation
Annelida is the correct answer because it is the only option that possesses all three characteristics: a closed circulatory system, protostome development, and many body segments. Mollusca and Arthropoda have a open circulatory system, while Echinodermata and Chordata have a deuterosome development. Therefore, Annelida is the only option that fits all the given criteria.
14.
Which of the following taxa contains organisms that are most distantly related?
Correct Answer
B. Class
Explanation
The correct answer is class. In the hierarchical classification system, class is a higher taxonomic rank than order, genus, family, and species. Organisms within the same class share more distant common ancestors compared to organisms within the same order, genus, family, or species. Therefore, organisms in different classes are most distantly related.
15.
A body cavity completely surrounded by tissue derived from the mesoderm that provides cushioning for internal organs is called
Correct Answer
B. A coelom.
Explanation
The correct answer is a coelom. A coelom is a body cavity that is completely surrounded by tissue derived from the mesoderm. It provides cushioning and protection for internal organs. The other options, such as an archenteron, a pseudocoelom, a gastrovascular cavity, and a pharynx, do not fully meet the criteria of being completely surrounded by mesodermal tissue.
16.
Organisms with prokaryotic cells are classified in the Domain
Correct Answer
D. Both A and B.
Explanation
The correct answer is both A and B because organisms with prokaryotic cells are classified in both the Domain Bacteria and the Domain Archaea. Prokaryotic cells lack a nucleus and membrane-bound organelles, and they are found in bacteria and archaea. These two domains are considered separate from the Domain Eukarya, which includes organisms with eukaryotic cells that have a nucleus and membrane-bound organelles.
17.
Multicellular, terrestrial autotrophs with cell walls of cellulose and alternating life cycles belong to the Kingdom
Correct Answer
D. Plantae.
Explanation
The given question is asking about the kingdom to which multicellular, terrestrial autotrophs with cell walls of cellulose and alternating life cycles belong. The correct answer is Plantae. This is because plants are multicellular organisms that are capable of producing their own food through photosynthesis. They have cell walls made of cellulose and undergo alternating life cycles, including both haploid and diploid stages. Therefore, the kingdom Plantae is the most appropriate choice.
18.
Multicellular heterotrophs that have the diploid stage as their dominant generation in the life cycle belong to the Kingdom
Correct Answer
A. Animalia.
Explanation
The given question is asking about the Kingdom to which multicellular heterotrophs belong, and specifically those that have the diploid stage as their dominant generation in the life cycle. The correct answer is Animalia because animals are multicellular heterotrophs, meaning they obtain their energy by consuming other organisms, and their life cycle typically involves a dominant diploid stage. Protista, Bacteria, Plantae, and Archaea do not fit these criteria.
19.
Molds, or deuteromycota, are grouped into this kingdom that consists of mostly multicellular organisms that are constructed of hyphae.
Correct Answer
E. Fungi
Explanation
The given statement describes molds as multicellular organisms constructed of hyphae. This characteristic aligns with the kingdom Fungi, which consists mostly of multicellular organisms like molds. Therefore, the correct answer is Fungi.
20.
Which of the following is the most specific category of classification?
Correct Answer
B. Family
Explanation
The most specific category of classification is family. In the hierarchy of biological classification, family is a level below order and above genus. It represents a group of related organisms that share common characteristics and have more similarities than those within the same order. This level of classification is more specific than order, division, and phylum, which encompass broader groups of organisms.