Question

In which group of animals, the coelom is filled with blood?

• A. Arthropoda
• B. Annelida
• C. Nematoda
• D. Echinodermata

Answer 1

The correct option is A

Arthropoda

The correct option A.

Explanation of the correct option:

Option A:

1. Blood flows through the coelom in Arthropods.
2. Mesoderm lines both sides of the gap between the body wall and the gut wall, known as the coelom.
3. Arthropoda with blood presents a real coelom called schizo coelom.
4. The body is segmented, triploblastic, and bilaterally symmetric.
5. Organ system-level organizations can be seen in them.
6. The head, thorax, and abdomen make up the body.
7. Their bodies have jointed appendages that aid in movement.
8. Blood is present in the coelomic cavity. Their circulatory system is open.
9. Compound eyes are present on the head.

Explanations of the incorrect options:

Option B:

1. Coelomate creatures, annelids have a cavity filled with fluid in which the intestines and other organs are hung.
2. Leeches' coeloms are reduced to a network of small canals, whereas archiannelids may completely lose their coelom.
3. In contrast, oligochaetes and polychaetes often have spacious coeloms.

Option C:

1. Despite having a space between their body wall and digestive system, worms do not consider this space to be a true coelom because it is not lined with tissue.
2. The term "pseudocoelomates" is thus sometimes used to describe nematodes.

Option D:

1. The mesoderm layer's coelom cavity is present.
2. However, if the coelom forms as a mesoderm pouch from the embryo's gut, it is known as an enterocoelom, and an enteron form from this type of coelom is known as an enterocoel, such as in Echnidermata and Chordata.

Final answer: The coelom is filled with blood in Arthropoda.