Choose the group of words that helps to show what pests means.
Remoras are small fish. They use a special fin to stick themselves to a shark. The remoras travel out to sea on the shark.
Remoras eat the pests that cling to the skin of a shark. By doing this, the remoras rid the shark of harmful bugs. This is good news for the
shark, of course. In
exchange for a free ride, the remoras help to keep the shark clean and healthy.