The choices can be found elsewhere and as follows:
A)
secretions that produce a hard protective skeleton.
B)
the inability to leave the reef and swim after prey.
C)
stinging cells that kill prey and discourage predators.
D)
symbiotic relationships with algae that photosynthesize and feed them.
I believe the correct answer is option B. One polyp feature that is detrimental rather than beneficial is the inability to leave the reef and swim after prey. Reefs begin when a polyp attaches itself to a rock on the sea floor, then divides, or buds, into thousands of clones. Hope this helps.
