A microsporophyll in Pinus has

Options

A. Two adaxial microsporangia
B. Two abaxial microsporangia
C. One abaxial microsporangium
D. Four abaxial microsporangia.

Answer

To solve the question regarding the structure of a microsporophyll in Pinus, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure**: A microsporophyll is a leaf-like structure that bears microsporangia, which are responsible for producing microspores. In Pinus, which is a type of gymnosperm, these structures are crucial for reproduction.

2. **Identify the Location of Microsporangia**: In Pinus, the microsporangia are located on the microsporophyll. The terms "adaxial" and "abaxial" refer to the positioning of these sporangia. Adaxial means facing towards the stem, while abaxial means facing away from the stem.

3. **Determine the Number of Microsporangia**: According to the information provided, each microsporophyll in Pinus typically bears two microsporangia.

4. **Specify the Positioning**: The microsporangia in Pinus are abaxial, meaning they are positioned away from the stem.

5. **Select the Correct Option**: Based on the above points, we can conclude that a microsporophyll in Pinus has 2 abaxial microsporangia. Therefore, the correct answer is option B.

### Final Answer:
**B. 2 abaxial microsporangia**

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