I need help solving this problem! It’s from the SAT!!

In an ecosystem, marsh snails feed on phytoplankton and painted turtles feed on marsh snails. pollution has resulted in the depletion of phytoplankton. what effect would this situation likely have on the population of marsh snails and painted turtles? as phytoplankton were destroyed, the population of marsh snails would most likely then the population of painted turtles would mostly likely a. 1. increase 2. decrease 3. stay the same b. 1. increase 2. decrease 3. stay the same