Question

State one possible reason that coral reefs exist only in shallow waters.

a) Lack of sunlight
b) Temperature fluctuations
c) Predation pressure
d) Need for symbiosis

Answer 1

Coral reefs exist only in shallow waters due to the need for symbiosis with photosynthetic unicellular algae. The algae live inside the coral, requiring sunlight for photosynthesis. This mutualistic relationship provides corals with nutrition and energy.

Step-by-step explanation:

One possible reason that coral reefs exist only in shallow waters is the need for symbiosis with photosynthetic unicellular algae. The algae live inside the coral and require sunlight for photosynthesis. Therefore, corals must be relatively close to the surface of the water where sunlight is abundant. This mutualistic relationship provides corals with the nutrition and energy they require to grow and survive in nutritionally poor waters.