In dicot root which tissue becomes dead due to activity of phellogen

Options

A. All tissue outside cortex
B. Tissue outside hypodermis
C. Tissue outside endodermis
D. Tissue outside pericycle

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which tissue in a dicot root becomes dead due to the activity of phellogen (cork cambium).

2. **Defining Phellogen**: Phellogen, also known as cork cambium, is a type of lateral meristem responsible for the secondary growth in plants. It produces cork cells that replace the epidermis in older stems and roots.

3. **Identifying the Role of Phellogen**: The primary function of phellogen is to facilitate secondary growth. As the plant grows, phellogen divides to produce new cells, which push older cells outward.

4. **Understanding Secondary Growth**: During secondary growth, the tissues that were previously located at the periphery of the root are pushed outward. This results in the crushing or death of these older tissues.

5. **Identifying the Tissues Involved**: In a dicot root, the arrangement of tissues includes:
- Epidermis (outermost layer)
- Cork
- Endodermis
- Pericycle
- Vascular bundles
- Pith

6. **Determining Which Tissues Die**: As the phellogen (cork cambium) produces new cork cells, the tissues located outside the pericycle (which include the epidermis, cork, and endodermis) will become dead due to being pushed outward and crushed.

7. **Conclusion**: The tissues that become dead due to the activity of phellogen in a dicot root are the tissues located outside the pericycle, specifically the epidermis, cork, and endodermis.

### Final Answer:
The tissues outside the pericycle (epidermis, cork, and endodermis) become dead due to the activity of phellogen in a dicot root.

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