AP BIOLOGY

Detailed explanation-1: -Many birds swallow sharp pebbles and grit and hold these rocks in a muscular part of their stomachs called the gizzard. The gizzard contracts and grinds the gastroliths against each other and against the food that the bird has swallowed (remember that birds have to swallow each bite whole).

Detailed explanation-2: -The avian digestive system is found in poultry. This system differs greatly from any other type. Since poultry do not have teeth, there is no chewing. Poultry break their feed into pieces small enough to swallow by pecking with their beaks or scratching with their feet.

Detailed explanation-3: -Ostriches have three stomachs and are particularly unusual as they have an extremely long intestine. They don’t have teeth so they eat small stones to help grind down their food. Therefore, they need three stomachs so that they can break down all of the different things that they eat.

Detailed explanation-4: -This is defined as the apparatus that allows the bird to prehend and swallow feed, a muscular channel (esophagus, proventriculus, gizzard, intestine) that transports the feed through the body, the salivary glands and pancreas that contribute digestive enzymes, the liver that secretes bile for fat digestion.