Look at the ocean system below.

plankton → shrimp salmon → humans

What will most likely happen if the plankton population decreases in this

ocean system?

O

A. All of the oxygen in the atmosphere will disappear.

O

B. Humans will have less salmon available to eat

O

C. The shrimp will completely disappear from the sea.

O

D. More salmon will move into the area.

B. Humans will have less salmon available to eat.

Explanation:

First off, you always want to be wary of choices that are kinda extreme. Take for example, choice A., which says All of the oxygen in the atmosphere will disappear. The problem doesn't say that the plankton population will go extinct, just decrease, so oxygen from the atmosphere won't completely disappear. There are also other sources of oxygen. Moving on, C. says that the shrimp will completely disappear from the sea. This is wrong because once again, plankton won't go extinct in the problem. The shrimp population will decrease but not go extinct. Next, D. Choice D is baloney because a decrease in plankton means less food for salmon, which means the salmon would die in the area. That leaves Choice B. Choice B. makes sense because of something called the bottom-up model, which states that an increase or decrease in the amount of organisms in a lower trophic level will affect the organisms in the above trophic levels. We can see that in action here; if the amount of plankton drop, the amount of shrimp salmon will drop, which means less salmon for humans.