[A]: Glucose oxidation is a slow process.
[R]: It consists of only two subprocesses.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states: "Glucose oxidation is a slow process."
- Glucose oxidation is indeed a crucial metabolic pathway that occurs in several stages, and it is generally considered a slow process compared to anaerobic processes like fermentation.

2. **Understanding the Reason**:
- The reason states: "It consists of only two subprocesses."
- This statement is incorrect. Glucose oxidation involves multiple subprocesses, not just two. The main stages include glycolysis, the link reaction (pyruvate oxidation), the Krebs cycle (citric acid cycle), and oxidative phosphorylation.

3. **Evaluating the Truth of Each Statement**:
- The assertion is true: Glucose oxidation is a slow process.
- The reason is false: It does not consist of only two subprocesses; there are four main stages involved in glucose oxidation.

4. **Choosing the Correct Option**:
- Based on the evaluation, we find that the assertion is true while the reason is false. Therefore, the correct answer is the third option: "Assertion is true and reason is false."

### Final Answer:
The correct option is: **Assertion is true and reason is false.**

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