The shape of pollen grains is generally and measure about ______`mu` m in daimter:

Options

A. Spherical, 100 - 200
B. Rod shaped, 25 - 50
C. Triangular, 1000 - 2000
D. Spherical, 25 - 50

Answer

### Step-by-Step Solution:

1. **Understanding Pollen Grains**: Pollen grains are the male gametophytes in flowering plants. They play a crucial role in reproduction by carrying male gametes.

2. **Shape of Pollen Grains**: The shape of pollen grains is generally spherical. This is a common characteristic across many species of flowering plants.

3. **Measurement of Diameter**: Pollen grains typically measure about 25 to 50 micrometers in diameter. This size range is standard for most pollen grains.

4. **Layers of Pollen Grains**: Pollen grains are surrounded by two layers: the outer layer called the exine and the inner layer called the intine. This structure is important for the protection and viability of the pollen.

5. **Conclusion**: Based on the information, the correct answer to the question is that the shape of pollen grains is generally spherical and they measure about 25 to 50 micrometers in diameter.

### Final Answer:
The shape of pollen grains is generally spherical and measures about 25 to 50 micrometers in diameter.

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