TeXes Science Practice Test

In the digestive system of an earthworm, which part is primarily responsible for digestion and absorption?

1. Pharynx

2. Gizzard

3. Intestine

4. Crop

The correct answer is: Intestine

The intestine of an earthworm plays a crucial role in both digestion and absorption. It is a long, coiled structure where the primary processes of breaking down food and absorbing nutrients occur. Once food passes through the pharynx and gizzard, where initial processing and grinding occur, the intestine receives the mixture. Here, enzymes further digest the food, allowing essential nutrients to be absorbed through the intestinal walls into the bloodstream of the earthworm. The other parts of the digestive system have specific and important functions but do not primarily handle digestion and absorption. The pharynx is involved in the intake of food, the gizzard functions to mechanically grind the food, and the crop serves as a temporary storage space for the ingested material, rather than actively participating in digestion and nutrient absorption.