Light penetrates the clear water of the open ocean more deeply than it does lake water. Phytoplankton is found deeper in the open ocean than in freshwater lakes.
What does this observation best indicate?
A Phytoplankton provides nutrients to consumers in the ecosystem.
B Phytoplankton reduces the light available to organisms at lower depths.
C Phytoplankton populations are limited by their ability to photosynthesize.
D Phytoplankton population growth is limited by the presence of marine salts.