Question

what is a bottom - up cascade?
a) an effect on apex predators caused by a change in primary producers
b) an effect on apex predators caused by a change in abiotic resources
c) an effect on primary producers caused by a change in apex predators
d) an effect on primary producers caused by a change in abiotic resources

Explanation:

In a bottom - up cascade, changes start from the base of the food web, typically primary producers. A change in primary producers can have a series of effects that ripple up the food web to apex predators.

Answer:

a) An effect on apex predators caused by a change in primary producers