What is the main idea of this passage? A. If the ocean gets too warm, the plants and animals that live in the ocean, from plankton to coral, must adapt or die off.

B. The ocean does many things that are crucial for the health of the environment, but ocean warming and rising acid levels are harming the ocean’s health.

C. The average depth of the ocean is 2.7 miles, and the ocean covers 70% of the Earth’s surface. Scientists aren’t sure what would happen if the Great Ocean Conveyor Belt stopped working, but they worry that it could affect the overall health of the planet.

D. Scientists aren’t sure what would happen if the Great Ocean Conveyor Belt stopped working, but they worry that it could affect the overall health of the planet.