In earthworm, haemoglobin is present in the dissolved state in

Options

A. Blood corpuscles
B. Both blood corpuscles and plasma
C. Plasma
D. Absent

Explanation

**Step-by-Step Solution:**

1. **Understanding Hemoglobin**: Hemoglobin is a protein found in blood that is responsible for transporting oxygen. It binds with oxygen molecules and is crucial for respiration in many organisms.

2. **Identifying the Organism**: The question specifically refers to the earthworm, which is a type of annelid. Understanding the circulatory system of earthworms is essential for answering the question correctly.

3. **Circulatory System of Earthworm**: Earthworms have a closed circulatory system, meaning that their blood is contained within vessels. The blood of earthworms is different from that of vertebrates.

4. **Presence of Hemoglobin**: In earthworms, hemoglobin is not found in red blood cells (as in vertebrates) but is instead present in the plasma, which is the liquid component of blood.

5. **Analyzing the Options**:
- **Option 1**: Blood corpuscle - This refers to blood cells, which in earthworms do not contain hemoglobin.
- **Option 2**: Both blood corpuscle and plasma - This is incorrect as hemoglobin is not present in blood cells in earthworms.
- **Option 3**: Plasma - This is the correct option, as hemoglobin is dissolved in the plasma of earthworms.

6. **Conclusion**: The correct answer is that in earthworms, hemoglobin is present in the dissolved state in the plasma.

**Final Answer**: Hemoglobin is present in the dissolved state in the plasma of earthworms.

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