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?