Which of the following is the correct sequence of the layers in a typical monocot root (from the outer surface to the pith) ?

Options

A. Pericycle, cortex, endodermis, epiblema.
B. Epiblema, endodermis, cortex, pericycle.
C. Epiblema, cortex, endodermis, pericycle
D. Epiblema, pericycle, cortex, endodermis

Answer

To determine the correct sequence of layers in a typical monocot root from the outer surface to the pith, we will analyze the structure of a monocot root step by step.

### Step-by-Step Solution:

1. **Identify the Outer Layer**: The outermost layer of a monocot root is called the **Epiblema**. This layer is similar to the epidermis and serves as a protective barrier.

**Hint**: Remember that "Epi" means upper, indicating that this layer is on the outside.

2. **Next Layer - Cortex**: Beneath the epiblema is the **Cortex**. This layer consists of parenchyma cells and serves to store food and transport water and nutrients to the inner layers.

**Hint**: Think of the cortex as the layer that protects and supports the inner vascular tissues.

3. **Following Layer - Endodermis**: The next layer is the **Endodermis**. This layer is characterized by a band of suberin (Casparian strip) that regulates the flow of water and nutrients into the vascular system.

**Hint**: The endodermis is the innermost layer of the cortex, acting as a gatekeeper for substances entering the vascular system.

4. **Next Layer - Pericycle**: Inside the endodermis, we find the **Pericycle**. This layer is responsible for the formation of lateral roots and is located just outside the vascular tissues.

**Hint**: The pericycle is crucial for root growth and development, as it is where lateral roots originate.

5. **Innermost Layer - Pith**: Finally, at the center of the root is the **Pith**. This layer consists of parenchyma cells and serves various functions, including storage and support.

**Hint**: The pith is the central part of the root, often involved in storage.

### Final Sequence:
From the outer surface to the pith, the correct sequence of layers in a typical monocot root is:
**Epiblema → Cortex → Endodermis → Pericycle → Pith**

### Conclusion:
Based on the analysis, the correct option that represents this sequence is the third option provided in the question.