A primary xylem :

Options

A. formed during primary growth
B. Is absent in monocot leaf
C. includes protoxylem and metaxylem
D. all of the above

Answer

### Step-by-Step Solution

1. **Understanding Primary Xylem**:
- Primary xylem is a type of xylem that is formed during the primary growth of a plant. This growth occurs at the tips of roots and stems, allowing the plant to increase in height and the roots to grow deeper.

2. **Components of Primary Xylem**:
- Primary xylem is composed of four main types of cells:
- **Tracheids**: Elongated cells that facilitate water transport.
- **Vessels**: Shorter, tube-like structures that also aid in water transport.
- **Xylem Fibers**: Dead cells that provide mechanical support and help in water transportation.
- **Xylem Parenchyma**: Living cells that store nutrients and assist in the transport of water over short distances.

3. **Functions of Primary Xylem**:
- The primary function of xylem, including primary xylem, is to transport water and dissolved minerals from the roots to other parts of the plant. This process occurs through passive transport, meaning it does not require energy.

4. **Types of Primary Xylem**:
- Primary xylem can be further categorized into:
- **Protoxylem**: The first xylem to develop, characterized by narrower vessels.
- **Metaxylem**: Develops later and has larger vessels.

5. **Identifying the Correct Option**:
- The question likely presents multiple options regarding primary xylem. Based on the explanation, the correct option would be the one that states that primary xylem is formed during primary growth.