Which of the following, pollen grains maintain their viability for months?

Options

A. Wheat, maize
B. Rice, wheat
C. Maize, rice
D. Tomato, bean

Answer

To determine which pollen grains maintain their viability for months, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Pollen Viability**: Pollen viability refers to the ability of pollen grains to germinate and fertilize ovules. Different species have varying durations of pollen viability.

2. **Identify the Options**: The options provided are wheat, maize, rice, tomato, and bean.

3. **Research Plant Families**:
- Wheat (Poaceae family)
- Maize (Poaceae family)
- Rice (Poaceae family)
- Tomato (Solanaceae family)
- Bean (Leguminaceae family)

4. **Examine Pollen Characteristics**:
- Pollen grains from the Poaceae family (wheat, maize, rice) typically have a shorter viability period.
- Pollen grains from the Solanaceae family (tomato) and the Leguminaceae family (bean) are known to have longer viability due to the presence of sporopollenin, a tough outer layer that protects pollen grains.

5. **Conclusion**: Based on the information about pollen viability, the pollen grains from tomato (Solanaceae) and bean (Leguminaceae) can maintain their viability for months.

6. **Final Answer**: Therefore, the correct answer is **tomato and bean**.