Question

spider crabs live in shallow areas of the ocean floor, and greenish - brown algae lives on the crabs backs, making the crabs blend in with their environment, and unnoticeable to predators. the algae get a good place to live, and the crab gets camouflage.
a commensalism
b mutualism
c competition
d parasitism

Explanation:

Mutualism is a symbiotic relationship where both species benefit. Here, the algae get a place to live and the crab gets camouflage. Commensalism is when one benefits and the other is unaffected. Competition is when species compete for resources. Parasitism is when one benefits at the expense of the other.

Answer:

B. Mutualism