When ocean temperatures rise, corals expel the colorful algae living in their tissues, turning them completely white. This process is known as "Coral Bleaching." Why is this a major concern for the environment?
(A) It makes the ocean look more beautiful to divers.
(B) Bleached corals provide more food for small fish.
(C) Corals are "nurseries" for 25% of all marine life; without them, the food chain collapses.
(D) White corals reflect sunlight and keep the water cool.