The relationship between the protistan zooxanthellae and the polyps of reef-building corals is best described as a(n):
A) facultative ectoparasitism.
B) facultative commensalism.
C) obligate endoparasitism.
D) obligate mutualistic endosymbiosis.
E) obligate commensalism.

Question

Quizplus · Accepted Answer

The relationship between the protistan zooxanthellae and the polyps of reef-building corals is obligate and mutualistic endosymbiosis. The zooxanthellae provide the coral polyps with photosynthetic products such as glucose and glycerol, while the coral polyps provide the zooxanthellae with a protected environment and access to nutrients. This interdependence is essential for the survival and growth of both organisms.

The Relationship Between the Protistan Zooxanthellae and the Polyps of Reef-Building