Question

The coelom in arthropods is reduced and known as ‘haemocoel’ because

• A. coelomic fluid flows in the blood vessel
• B. blood flows in the blood vessels present in the coelom
• C. coelom is filled with haemoglobin
• D. blood flows in the coelom

Answer 1

The correct option is D

blood flows in the coelom

The correct option is D:

Explanation of the correct option:

Option D:

1. Having an open circulatory system, arthropods have freely moving organs inside a coelom(cavity) filled with body fluids which protect them from shocks.
2. Since the body cavity is reduced and filled with blood, it is called haemocoel.
3. Haemocoel ('Haem' refers to haemoglobin content present in RBCs and 'Coel' refers to the cavity), can act as a hydrostatic skeleton.

Explanation of the incorrect option:

Option A:

The coelomic fluid doesn't flow in blood vessels, blood does.

Option B:

Blood flows in the blood vessel but that doesn't reduce cavity size and hence is not related to coelom.

Option C:

1. Haemoglobin is a protein present in red blood cells.
2. In arthropods, Coelom is filled with blood which constitutes plasma, red blood cells, white blood cells, and platelets.

Final answer: The coelom in arthropods is reduced and known as ‘haemocoel’ because blood flows in the coelom.