November 28, 2015

Homework Help: Biology

Posted by mysterychicken on Thursday, March 4, 2010 at 5:59pm.

20. One difference between a gastrovascular cavity and a one-way digestive system is the presence or absence of
a. cell specialization
b. digestive enzymes
c. digestion within body cells
d. a moist membrane for nutrient diffusion

21. In an open circulatory system,
a. water is drawn into the mantle cavity to provide oxygen to body tissues
b. lungs branch into small tubules to provide oxygen to tissues
c. wastes are eliminated directly to the environment from tissues
d. body tissues are bathed directly in fluid containing oxygen

22. The system that does not allow for direct contact between oxygen-carrying cells and tissues is called
a. a one-way digestive system
b. the excretory system
c. a closed circulatory system
d. an open respiratory system


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