1. Respiratory Systems
Contrast the breathing processes in fish, crustaceans, and clams.
Make a Venn diagram of respiratory vs. circulatory structures in mammals
Explain the role of diffusion in respiration in all animals.
Why must earthworm bodies remain moist?
What is the outermost layer of cells called in a human? In an earthworm?
How are alveoli related to lungs?

2. Circulatory Systems
What is the purpose of circulation?
What is hemolymph?
Air contains ~20% dissolved oxygen while water contains ~0.6 to 0.8% dissolved oxygen. How does this limit circulation speed in different (closed) circulatory systems?
Why is efficiency improved if oxygen-rich and oxygen-poor blood travel in different loops? (What is the job of a single red blood cell?)

3. What is the difference between a ventricle and an atrium?
What do open and closed circulatory systems have to do with blood pressure?
Application Questions
Horror movie scenario: Giant ants take over the world. Why is this physically impossible? (2 reasons)
Mollusks can be bivalves (clams), gastropods (snails, slugs), and cephalopods (squids, octopi). Cephalopods are the only mollusks with a closed circulatory system. Why?