Part a: which claims are supported by evidence from the graph?

circle the two correct answers.

a. a large sheephead population will cause the sea urchin population to decrease.

b. sea urchin survival depends on a stable sheephead population

c. the sea urchin population has a limiting effect on the sheephead population.

d. as the sea urchin population decreases, the population of sheephead decreases due to starvation.

e. the size of the sheephead population has a direct effect on the size of the sea urchin population

part b: which statement uses information from the graph that supports the answer to part a (previous question)?

a. the sea urchin population with sheephead present decreased between 1980 and 1982

b. the sea urchin population with sheephead absent was smaller in 1982 than it was in 1980.

c. the sea urchin population with sheephead present was higher in april 1982 than it was in june 1981.

d. the sea urchin populations with sheephead present and with sheephead absent were the same in november 1980.