Answer:
Gizzard
Explanation:
The gizzard is the thick-walled muscular structure present in the earthworm. Its function is to grind the food into smaller pieces with the help of sand grains and to soften it. Earthworm intake sand grains along with food.
Birds also have thick and muscular gizzard. The function is the same as in earthworm, that is, to carry out mechanical digestion of food with help of gravel that birds swallow along with their food and to make it soft.
