Assertion: Smaller the organism higher is the rate of metabolism per gram weight.
Reason: The heart rate of a six-month-old baby is much lower than that of an old person.

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

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "Smaller the organism, higher is the rate of metabolism per gram weight." This implies that smaller organisms tend to have a higher basal metabolic rate (BMR) when measured per unit of body weight.

2. **Explaining Basal Metabolic Rate (BMR)**: BMR is the amount of energy expended while at rest, and it reflects the energy requirements of the body. It is influenced by factors such as total body weight and muscle mass. Generally, BMR is inversely related to the size of the organism; smaller organisms have a higher BMR per gram of body weight compared to larger organisms.

3. **Evaluating the Reason**: The reason provided states, "The heart rate of a six-month-old baby is much lower than that of an old person." To analyze this, we need to compare the heart rates. A six-month-old baby typically has a heart rate of about 110-112 beats per minute, while an adult's heart rate ranges from 60-100 beats per minute. Therefore, the assertion that the heart rate of a six-month-old baby is lower than that of an old person is incorrect, as the heart rate of the baby is higher.

4. **Determining the Relationship**: While both the assertion and reason are true statements, they are not related to each other. The assertion about metabolism does not depend on the heart rate of a baby versus an old person. Therefore, the reason does not correctly explain the assertion.

5. **Conclusion**: Based on the analysis, the assertion is true, but the reason is false. Hence, the correct answer is that the assertion is true, and the reason is false.

**Final Answer**: Assertion is true, Reason is false.

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