In a multicellular animal, the circulatory system exchanges materials with the external environment using specialized exchange surfaces. Which of the following is not an example of such an exchange surface?
A)lung
B)muscle
C)skin
D)intestine
E)kidney

Question

Quizplus · Accepted Answer

Muscles are not specialized exchange surfaces, as they do not directly exchange materials with the external environment. Instead, they receive nutrients and oxygen from the circulatory system through blood vessels that run alongside or within the muscles.

In a Multicellular Animal, the Circulatory System Exchanges Materials with the External