What is the role of the gizzard in bird digestion?

a. to store food for easy means of regurgitation to offspring

b. to chemically digest food

c. to store gastroliths that physically grind up food

d. to produce saliva to start the digestive process

The correct answer is C. To store gastroliths that physically grind up food.

Explanation

The gizzards, are a special part of the digestive system of some animals such as birds, fish, and reptiles whose main function is to crush the food that the animal ingests, for this task, the gizzards contain in their interior gastroliths, a kind of polished stones, that grinds the food that the animal eats. The gizzards represent an important part for these animals because many of them do not have teeth to crush their food and feed on it. So, the correct answer is C. To store gastroliths that physically grind up food.