AP BIOLOGY

Detailed explanation-1: -A new study shows that chickens, which don’t have teeth, still have the genes that make them, and in special cases, those genes can be switched back on. Scientists now think that as animals evolve, they lose the ability to turn those genes on at the right time during development-not the genes themselves.

Detailed explanation-2: -Like other birds, chickens don’t have teeth. Chickens do not have teeth in the traditional sense; instead, they have beaks.

Detailed explanation-3: -Birds do not have teeth. Without teeth, a bird cannot chew its food down to bits in its mouth like humans do. As detailed in the textbook Ornithology by Frank B. Gill, birds must instead rely on the muscular stomach-like pouch called the gizzard to crush down their food.

Detailed explanation-4: -When a chicken egg is incubated, the egg tooth begins to develop on the seventh day. As hatching time approaches the egg tooth becomes sharp and hard. Approximately three days before the chick hatches, it uses the egg tooth to break through the inner membrane at the blunt end of the egg.