Question

by eliminating the shake from the ecosystem, what was the impact of the fence?
a) prevented a bottom - up cascade
b) caused a top - down cascade
c) caused a bottom - up cascade
d) prevented a top - down cascade

Explanation:

In an ecosystem, when a top - predator (like a shake, assuming it's a predator here) is removed by a fence, it can cause a top - down cascade. A top - down cascade occurs when changes in top - predator populations affect lower trophic levels. Removing the predator would likely cause an increase in its prey population, which can then have further effects on the plants and other organisms in the ecosystem. So, the fence caused a top - down cascade by eliminating the predator.

Answer:

b) Caused a top - down cascade