Answer:
excretory and respiratory
The order of steps for the digestion of proteins will be;
In mechanical digestion, the teeth grind food and break it in to smaller parts.
Churning and the enzyme pepsin break down protein in the stomach
The pancreas releases enzymes trypsin and chymotrypsin
Tryspsin and chymotrypsin act on the proteins to break them down in the duodenum
Amino acids are absorbed by the capillaries in the Jejunum and lastly
The amino acids enter the blood stream and are circulated throughout the body.
Birds, just like humans, have a four-chambered heart.
