Which statement is true about earthworm ?

Options

A. Blood is blue
B. Blood is red but haemoglobin is dissolved in plasma
C. Blood pigment is haemocyanin
D. Blood is red but haemoglobin is dissolved in RBC's

Answer

To determine which statement is true about earthworms, we can analyze each option provided:

1. **Option 1: Blood is blue.**
- This statement is incorrect. Earthworm blood is not blue; it is red due to the presence of hemoglobin.

2. **Option 2: Blood is red but hemoglobin is dissolved in plasma.**
- This statement is correct. Earthworm blood is indeed red, and the hemoglobin is dissolved in the plasma, not contained within red blood cells, as earthworms do not have RBCs.

3. **Option 3: Blood pigment is hemocyanin.**
- This statement is incorrect. Hemocyanin is a copper-based pigment found in some other invertebrates, but earthworms use hemoglobin, which is iron-based.

4. **Option 4: Blood is red but hemoglobin is dissolved in RBCs.**
- This statement is incorrect. While the blood is red, hemoglobin in earthworms is not dissolved in red blood cells because they lack RBCs.

Based on this analysis, the true statement about earthworms is:

**Correct Answer: Blood is red but hemoglobin is dissolved in plasma.**

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