Question

While dissecting an earthworm, you notice a closed tube that sits atop the digestive tract. Within each segment, this dorsal tube has a pair of branches that extend to connect with a similar ventral tube. What are you looking at?

A) a closed circulatory system
B) a nerve cord
C) an excretory system
D) an open circulatory system

Answer 1

A.

Explanation:

1. The circulatory system; in earthworm is a closed type . (blood is contained in vessels) .

2. An earthworm circulates blood through vessels only.

3. There are 3 main vessels in earthworm that supply the blood to organs and whole body.

These vessels are called as i) dorsal blood vessels,ii) the aortic arches and iii) ventral blood vessels.

4. The aortic arches of earthworm function just like as human heart.