Medullary rays are mainly

Options

A. composed of sclerenchyma cells
B. involved in storage of food
C. involved in radial transport of food and water
D. involved in vertical transport of food and water

Answer

**Step-by-Step Solution:**

1. **Understanding Medullary Rays**: Medullary rays are structures found in the stems of dicot plants. They are composed primarily of parenchymatous cells, which are a type of ground tissue.

2. **Identifying the Composition**: The question asks what medullary rays are mainly composed of. The transcript mentions that they are made up of parenchyma cells, not sclerenchyma cells. Therefore, the first option regarding composition is incorrect.

3. **Function of Medullary Rays**: The transcript explains that medullary rays are involved in the radial transport of food and water. This means they help in the movement of nutrients and water horizontally across the stem.

4. **Evaluating Other Options**:
- The option stating that medullary rays are involved in the storage of food is incorrect because while some parenchyma cells can store food, it is primarily the phloem parenchyma that is responsible for food storage.
- The option regarding vertical transport of food and water is also incorrect, as vertical transport is mainly the function of xylem (for water) and phloem (for food).

5. **Conclusion**: Based on the analysis, the correct answer is that medullary rays are involved in the radial transport of food and water.

**Final Answer**: Medullary rays are mainly involved in radial transport of food and water.

---