- It is not always easy to categorize a particular case of symbiosis.
Suppose a certain species of snail is always found living on a
certain coral. No one has found evidence that the snail harms the
coral, so the relationship is classified as commensalism. How
would you go about testing this hypothesis? What kinds of
observations might lead to the conclusion that the snail is a
parasite, or that it has a mutualistic relationship with the coral?