RQ is less than one for

Options

A. Carbohydrate
B. Organic acid
C. Starch
D. Protein.

Answer

### Step-by-Step Solution:

1. **Understanding RQ (Respiratory Quotient)**:
- RQ is defined as the ratio of carbon dioxide (CO2) produced to oxygen (O2) consumed during respiration.
- Mathematically, RQ = CO2 produced / O2 consumed.

2. **Identifying RQ Values for Different Substrates**:
- Carbohydrates: RQ is approximately 1 (specifically, it can be considered as 1 for glucose).
- Organic Acids: RQ is typically greater than 1.
- Starch: Similar to carbohydrates, the RQ is also around 1.
- Proteins: The RQ for proteins is generally less than 1.

3. **Analyzing the Options Given**:
- **Option A (Carbohydrates)**: RQ is approximately 1. Not the answer.
- **Option B (Organic Acids)**: RQ is greater than 1. Not the answer.
- **Option C (Starch)**: RQ is also approximately 1. Not the answer.
- **Option D (Proteins)**: RQ is less than 1. This is the correct answer.

4. **Conclusion**:
- The correct answer is **Option D (Proteins)**, as the respiratory quotient for proteins is less than 1.