Explanation and Application of Concepts:

1. Explain why a sea star that lives in the ocean (3.5 % salt) would not survive long if you took it home and put it in a bathtub filled with tap water (0.0 % salt).

2. During digestion, nutrients are absorbed across the wall of the small intestine into your blood stream. Explain why the long length (20 ft.) and numerous finger-like projections along the internal surface of the small intestine serve to optimize this important functions.

3. Just as you go to grab a head of lettuce at the local grocery store, the automatic misting system most large grocery chains have installed comes on. What are they spraying on the lettuce and why?

4. In the movie, Evolution, a giant "blob" - like organism consisting of a single cell grows to huge proportions (as big as a mountain). Although its plasma membrane is strong enough to contain its mass, based on what you learned today about factors affecting the rate of transport, could such a huge creature made up of only a single cell exist?Why or why not?