The __ is a very specialized structure which is very high in tendons and muscles in poultry. Proventriculus Gizzard Crop Small intestine

## Step 1<br />The problem is asking us to identify a specific part of a bird's digestive system that is highly specialized and contains a large amount of tendons and muscles. The options provided are Proventriculus, Gizzard, Crop, and Small Intestine.<br /><br />## Step 2<br />The Proventriculus is a part of the bird's stomach where food is mixed with digestive juices. It does not contain a large amount of tendons and muscles.<br /><br />## Step 3<br />The Crop is a pouch that stores food before it moves to the stomach. It also does not contain a large amount of tendons and muscles.<br /><br />## Step 4<br />The Small Intestine is where most of the digestion and absorption of food takes place. It does not contain a large amount of tendons and muscles.<br /><br />## Step 5<br />The Gizzard, on the other hand, is a specialized part of the bird's stomach that grinds up food. It contains a large amount of tendons and muscles, which allows it to perform this function.