The clownfish readily swims among the tentacles of the sea anemones; the parrotfish avoids them. One hypothesis for the clownfish's apparent immunity is that they slowly build a tolerance to the sea anemone's toxin. A second hypothesis is that a chemical in the mucus that coats the clownfish prevents the nematocysts from being triggered. Which of the following graphs supports the second, but not the first, of these hypotheses?

Question

Quizplus · Accepted Answer

Graph C shows that the mucus of the clownfish prevents the nematocysts from being triggered, as there is no reaction when the mucus is applied to the sea anemone. Graphs A, B, and D all show some level of tolerance being built over time, supporting the first hypothesis as well.

The Clownfish Readily Swims Among the Tentacles of the Sea