Answer:
The correct option is D) Hydrosphere
Explanation:
The corals present int he hydrosphere interact with the algae through a endosymbiotic relationship. This endosymbiotic relationship helps to maintain the health of the corals and the reefs. However, at a certain time, the coral reefs might expel the algae living inside it. This phenomenon is termed as coral bleaching. The corals generally expel the algae when they are under stress situations such as changes in temperature or availability of nutrients.
