The most active zone of root is

Options

A. Epidermis
B. cortex
C. endodermis
D. pericycle

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of the Root**:
- The root consists of several layers: Epidermis, Cortex, Endodermis, and Pericycle. Each layer has distinct characteristics and functions.

2. **Identifying the Epidermis**:
- The epidermis is the outermost layer of the root, also known as epiblema. It is primarily responsible for the formation of root hairs, which help in the absorption of water and nutrients.

3. **Examining the Cortex**:
- The cortex is located beneath the epidermis and is composed of thin-walled parenchyma cells. These cells have intercellular spaces that facilitate gas exchange and storage.

4. **Analyzing the Endodermis**:
- The endodermis is the innermost layer of the cortex, consisting of a single layer of barrel-shaped cells. It is impermeable to water due to the presence of a waxy substance called suberin, which helps regulate water movement.

5. **Understanding the Pericycle**:
- The pericycle is a layer of thick-walled parenchyma cells located just inside the endodermis. It is crucial for the initiation of lateral roots and contains vascular cambium, which is responsible for secondary growth.

6. **Determining the Most Active Zone**:
- The pericycle is identified as the most active zone of the root due to its high meristematic activity. This means that the cells in the pericycle are rapidly dividing, contributing to the growth and development of the root.

7. **Conclusion**:
- Based on the analysis of each layer, the correct answer to the question "The most active zone of the root is" is **Pericycle (Option D)**.

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