20. Three common characteristics of adult vertebrates are
a. skull, notochord, and complex organ system
b. backbone, segmentation, and open circulatory system
c. two pairs of jointed appendages, cephalization, and internal skeleton
d. hydrostatic skeleton, bilateral symmetry, and true coelom
D?
24. A backbone, gills, and single-loop blood circulation are characteristics of
a. cartilaginous fish
b. gelatinous fish
c. jawless fishes
d. all of the above
D?
31. Endothermic metabolism, complete ventricle division in heart, and a very efficient respiratory system are characteristics of
a. reptiles
b. birds
c. amphibians
d. fish
B?
-MC
For question 20, the correct answer is a. skull, notochord, and complex organ system. To arrive at this answer, you need to understand the characteristics of adult vertebrates.
1. A skull: All adult vertebrates have a well-developed skull that protects the brain and sensory organs.
2. Notochord: The notochord is a long, flexible rod that runs along the back of the embryo. In some vertebrates, such as fish, it is replaced by the backbone in adulthood. However, it is still present in embryos of all vertebrates and in some adult vertebrates like jawless fish.
3. Complex organ system: Adult vertebrates have well-developed organ systems, including a circulatory system, respiratory system, digestive system, nervous system, and reproductive system.
For question 24, the correct answer is a. cartilaginous fish, b. gelatinous fish, and c. jawless fishes. To arrive at this answer, you need to understand the characteristics of these types of fish.
1. Cartilaginous fish: Examples include sharks, rays, and skates. They have a backbone made of cartilage instead of bone, gills for respiration, and a single-loop blood circulation system.
2. Gelatinous fish: These are also known as jellyfish. They don't have a backbone but have a gel-like body structure. They possess gills for respiration and a single-loop blood circulation system.
3. Jawless fishes: This category includes lampreys and hagfish. They do not possess jaws, a backbone, or paired fins. They have gills and a single-loop blood circulation system.
For question 31, the correct answer is b. birds. To arrive at this answer, you need to understand the characteristics of birds.
1. Endothermic metabolism: Birds are warm-blooded animals, meaning they generate and maintain their body temperature internally.
2. Complete ventricle division in heart: Birds have a four-chambered heart with completely separated ventricles, which allows for efficient oxygenation and distribution of oxygenated blood throughout the body.
3. Very efficient respiratory system: Birds have highly efficient respiratory systems. They have small and lightweight lungs but also utilize air sacs that extend into the hollow bones, allowing for constant airflow and efficient gas exchange.
Keep in mind that these answers are based on the information provided, and the correct answer may vary depending on the context or additional information not provided.