Answer:
Are not affected by disease or bleaching.
Step-by-step explanation:
A healthy coral shows shades of olive green, brown, tan and pale yellow. A healthy coral in a host of many species of tropical animals, some others find their food that shelters in the crevices of stony corals. Abnormal paling color is a bad sign in corals when they are stressed out and they begin to bleach. when this happens the edge of the affected tissue turns from light to dark, in comparison to disease where the difference between healthy and diseased tissue is seen as a distinct line. There are many diseases that cause coral's abnormal bleaching color. for example, white band, white botch, coprophilia, and others.