Which is fuctional unit of inheritance

Options

A. Ciston
B. Intron
C. Chromosome
D. Gene

Answer

### Step-by-Step Solution:

1. **Understanding Genetic Material**: The question asks for the functional unit of inheritance. To answer this, we first need to understand what genetic material is. Genetic material is primarily DNA (deoxyribonucleic acid).

2. **Defining the Functional Unit**: The functional unit of inheritance refers to the basic unit that carries genetic information. In the context of DNA, this unit is known as a gene.

3. **Analyzing the Options**:
- **Sistron**: This term is related to genetic organization but is not commonly used to refer to the functional unit of inheritance.
- **Intron**: Introns are non-coding regions of a gene and do not carry the information necessary for inheritance.
- **Chromosome**: Chromosomes are structures that contain many genes, but they are not the smallest functional unit of inheritance.
- **Gene**: A gene is a specific sequence of DNA that encodes for a trait and is the basic unit of heredity.

4. **Conclusion**: Based on the definitions and analysis of the options, the correct answer to the question "Which is the functional unit of inheritance?" is **gene**.

### Final Answer:
The functional unit of inheritance is **gene**.

---