The innermost layer of bark is :-

Options

A. Primary phloem
B. Secondary phloem
C. Periderm
D. Phelloderm

Answer

To determine the innermost layer of bark, we need to analyze the layers that make up the bark structure in plants. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understanding Bark Structure**: The bark of a plant consists of multiple layers. The outermost layer is known as cork, followed by the cork cambium, and then the pheloderm.

2. **Identifying the Layers**:
- **Cork**: This is the outermost protective layer of the bark.
- **Cork Cambium**: This is the layer that produces cork cells.
- **Pheloderm**: This is the layer located just beneath the cork cambium.

3. **Recognizing the Periderm**: The combination of cork, cork cambium, and pheloderm is collectively referred to as the periderm. However, this is not the innermost layer.

4. **Examining the Phloem Layers**:
- **Secondary Phloem**: This layer is located beneath the pheloderm and is responsible for the transport of nutrients.
- **Primary Phloem**: This is found outside the vascular cambium and is not the innermost layer.

5. **Conclusion**: The innermost layer of the bark is the **secondary phloem**. Therefore, among the options provided (primary phloem, secondary phloem, periderm, pheloderm), the correct answer is **secondary phloem**.

### Final Answer:
The innermost layer of bark is **secondary phloem**.