The relationship between clownfish and anemones is considered a mutualism. Which of the following statements provides the best evidence for the relationship being a mutualism rather than another type of symbiotic association?

Anemones can sting and consume fish that swim into their tentacles, but their stingers are repressed by chemicals secreted from the scales of clownfish.
Clownfish are male at birth, then can become female and become more dominant later in their lives.
Clownfish are protected by the anemone's tentacles and move water through the anemone, clean debris, and attract other fish that the anemone may eat.
Multiple clownfish may live in a single anemone at one time, even though some anemones may only host a single clownfish.