Question

most ocean food chains depend on phytoplankton as primary producers. where in the ocean do phytoplankton live? a. throughout all ocean waters, because phytoplankton can tolerate a wide range of temperature and light conditions b. within about 200 meters of the ocean shoreline, because phytoplankton depend on nutrients that wash into the water from land c. within about 200 meters of the ocean surface, because phytoplankton require light to survive d. attached to shells along the ocean floor, because phytoplankton cannot float

Explanation:

Phytoplankton are photosynthetic organisms and require light for photosynthesis. Light penetrates only the upper - most layers of the ocean, approximately the top 200 meters.

Answer:

C. within about 200 meters of the ocean surface, because phytoplankton require light to survive