mutualism
When a sea snail dies, its shell eventually washes up on shore, where the hermit crab uses it as its new home. Therefore this would be commensalism, however since the snail already died there is no living symbiosis.
radial
Sea Anemone and Clown Fish have a Mutualistic Symbiotic relationship, meaning both members derive some benefit from the arrangement. In this case, the fish gains shelter and protection from the bigger meaner things that swim around the reefs, and the Anemone gains a live-in maid service that takes care of pretty much all the potential parasites that would otherwise endanger it.
crab
It depends on what kind of crab it is. What kind of BS answer is that "It depends on the type of crab?" Give examples or just don't say anything!
The relationship of the clown fish and sea anemone is symbiotic in that the clownfish, having a coating of mucous that makes it immune to the anemone's deadly sting, can swim in safety in the anemone's tentacles, meanwhile attracting other fish as food for the anemone.
boxer
ananaschomosis
Boxer
meat
well i guess it depends on what kind of crab it is. but i think a crab can't hurt you without claws.
The Horseshoe crab - lays about 4000 eggs