Use this graph for question 1.

1. The best explanation for the shape of this growth response curve is that
a. the plant requires air in the soil for photosynthesis.
b. the roots are able to absorb more nitrogen (N₂) in high levels of air.
c. most of the decrease in weight at low air levels is due to transpiration from the leaves.
d. increased soil air produces more root mass in the soil but does not affect the top stems and leaves.
e. the roots require oxygen for respiration and growth.

2. Root cells are, by comparison with soil water, generally
a. isotonic
b.hypertonic
c. hypotonic
d. variant between hypotonic and hypertonic extremes
e. impermeable.

3. Which one of the following is not a functionally analogous pair?
a. guinea pig's caecum - cow's rumen
b. root hairs - intestinal villi
c. cnidaria nematocyst - tongue
d. sea star's cardiac stomach - fungal hyphae
e. none of the above.

4. The vascular bundle in the shape of a single central cylinder in a root is called the
a. cortex.
b. stele
c. endodermis.
d. periderm.
e. pith.

5. What is the mutualistic association between roots and fungi called?
a. nitrogen fixation
b. Rhizobium infection
c. mycorrhizae
d. parasitism
e. root hair enhancement

6. Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition
a. from organic matter.
b. by preying on animals.
c. by ingesting it.
d. by consuming living, rather than dead, prey.
e. by using enzymes to digest their food.

7. Which one of the following does not belong with the others?
a. jellyfish
b. earthworm
c. clam
d. sea star
e. shark

8. Which of the following can extend the stomach through their mouth to feed.
a. sea stars
b. sea urchins
c. sea slugs
d. zebras
e. earthworms

9. Adult lampreys attach onto large fish and feed regularly on their body fluies. Given this continuous supply of food, which one of the following is most likely missing in lampreys?
a. liver
b. pancreas
c. intestine
d. stomach
e. gallbladder

10. In general, herbivous mammals have molars modified for
a. cutting
b. ripping
c. grinding
d. splitting
e. piercing

11. In which group of animals would you expect to find a relatively long cecum?
a. carnivores
b. herbivores
c. autotrophs
d. heterotrophs
e. omnivores

12. Which one of the following do not need a digestive system?
a. heterotrophs
b. autotrophs
c. herbivores
d. omnivores
e. carnivores

13. Increasing the surface area facilitates which of the following digestive processes?
a. hydrolysis
b. absorption
c. elimination
d. A and B only
e. A, B, and C

14. Which of the following is an advantage of a complete digestive system over a gastrovascular cavity?
a. extracellular digestion is not needed.
b. Specialized regions are possible.
c. Digestive enzymes can be more specific.
d. Extenstive branching is possible.
e. Intracellular digestion is easier.

15. Some nutrients are considered essential in the diets of certain animals becausea
a. only those animals use the nutrients.
b. they are subunits of important polymers.
c. they cannot be manufactured by the organism.
d. they are necessary coenzymes.
e. only some foods contain them.