Which of the following is a correct statement about an organism and its environment?
- Animals isolated from their environments live longer than those exchanging matter with the environment.
- An animal is a closed system that is separate and distinct from its environment.
- The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.
- The gastrovascular cavity provides the nutrient exchange surface in mammals.
- None of the choices is correct.
Answer: The interstitial fluid is the exchange medium between body cells and the circulatory system in vertebrate animals.