Polar Bears Are Threatened by a Reduction in the Amount

Multiple Choice

Polar bears are threatened by a reduction in the amount of phytoplankton in the ocean because

A) polar bears are at the top of the food chain in which phytoplankton are the primary producers.
B) polar bears use phytoplankton as an important source of vitamins.
C) phytoplankton are bioindicators of the amount of ice in the polar bear's ecosystem.
D) polar bears become covered with phytoplankton as camouflage when they forage on the tundra.