AP BIOLOGY

Detailed explanation-1: -The typical feather consists of a central shaft (rachis), with serial paired branches (barbs) forming a flattened, usually curved surface-the vane. The barbs possess further branches-the barbules-and the barbules of adjacent barbs are attached to one another by hooks, stiffening the vane.

Detailed explanation-2: -The presence of feathers covering the entire body and flight are characteristic features of birds. Some birds do not fly but their body is covered with feathers. Similarly, some mammals can fly but their body is not covered with feathers. Thus, the correct answer is option A.

Detailed explanation-3: -What are the functions of feathers? (Answers: flight, insulation, defense, display, camouflage, waterproofing)

Detailed explanation-4: -Protection. Feathers help shield birds’ bodies from bruises and scrapes. Communication. Hundreds of bird species use their feathers to “talk, ” especially when looking for a mate.