In dicots the most common pollen tetrad is

Options

A. Isobilateral
B. Tetrahedral
C. Linear
D. Decussate.

Answer

### Step-by-Step Solution:

1. **Understanding Pollen Tetrads**:
- Pollen grains are the male gametophytes in seed plants and are produced from microspores. A group of four haploid microspores forms a structure known as a tetrad.

2. **Types of Pollen Tetrads**:
- The arrangement of pollen tetrads can vary. The common arrangements include:
- **Isobilateral**: All four pollen grains are in one plane. This arrangement is typically found in monocots.
- **Tetrahedral**: The four pollen grains are arranged in a three-dimensional tetrahedral shape. This arrangement is most commonly found in dicots.
- **Linear**: The pollen grains are arranged in a straight line.
- **Decassate**: The pollen grains are arranged at right angles to each other.

3. **Identifying the Most Common Type in Dicots**:
- Among the options provided, the tetrahedral arrangement is specifically noted as the most common type of pollen tetrad found in dicots.

4. **Conclusion**:
- Therefore, the answer to the question "In dicots, the most common pollen tetrad is" is **tetrahedral**.

### Final Answer:
The most common pollen tetrad in dicots is **tetrahedral**.

---