Assertion` :-` Major part of `CO_(2)` is transported in the form of sodium bicarbonate.
Reason `:-` 0.3 ml of `CO_(2)` is transported per 100ml of blood in dissolved state in plasma of blood.

Options

A. If both Assertion & Reason are true and the
reason is the correct explanation of the
assertion, then mark (1)
B. If both Assertion & Reason are trye but the
reason is not the correct explanation of the
assertion , then mark (2)
C. If Assertion is true statement but Reason is
fakse, then mark (3)
D. If both Assertion and Reason are false
statements, then mark (4)

Answer

### Step-by-Step Solution

1. **Understanding the Assertion**: The assertion states that the major part of carbon dioxide (CO₂) is transported in the form of sodium bicarbonate. This is true because approximately 70% of CO₂ is indeed transported as bicarbonate ions (HCO₃⁻) in the blood.

2. **Understanding the Reason**: The reason states that 0.3 ml of CO₂ is transported per 100 ml of blood in a dissolved state in the plasma. This is also true, as a small percentage of CO₂ (about 7%) is carried dissolved in plasma.

3. **Analyzing the Relationship**: While both statements are correct, they refer to different aspects of CO₂ transport. The assertion focuses on the predominant form of CO₂ transport (as bicarbonate), while the reason discusses the amount of CO₂ transported in a dissolved state in plasma.

4. **Conclusion**: Since both the assertion and reason are true but not directly related to each other, we conclude that the assertion is correct, the reason is correct, but the reason does not explain the assertion. Therefore, the correct answer is that both A and R are correct, but R is not the correct explanation of A.

### Final Answer:
Both the assertion and reason are true, but the reason does not explain the assertion.