Variability found in DNA is due to

Options

A. Sugars
B. Nitrogen bases
C. Phophates
D. Glycosidic bonds.

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Structure**: DNA (deoxyribonucleic acid) is composed of three main components: a sugar (deoxyribose), phosphate groups, and nitrogenous bases.

2. **Identifying the Components**:
- **Sugar**: In DNA, the sugar is always deoxyribose. There is no variability in the type of sugar present across different DNA molecules.
- **Phosphate Groups**: The phosphate groups in DNA are also uniform; they do not contribute to variability.
- **Nitrogenous Bases**: The variability in DNA primarily arises from the nitrogenous bases.

3. **Types of Nitrogenous Bases**: There are two categories of nitrogenous bases in DNA:
- **Purines**: These are double-ring structures and include adenine (A) and guanine (G).
- **Pyrimidines**: These are single-ring structures and include thymine (T) and cytosine (C).

4. **Base Pairing**: The nitrogenous bases pair specifically:
- Adenine pairs with thymine (A-T) through two hydrogen bonds.
- Cytosine pairs with guanine (C-G) through three hydrogen bonds.
This specific pairing contributes to the genetic code and variability.

5. **Conclusion**: The variability found in DNA is due to the different nitrogenous bases (A, T, C, G) that can be arranged in various sequences along the DNA strand. This sequence variation is what leads to genetic diversity among organisms.

**Final Answer**: Variability found in DNA is due to the different nitrogenous bases present in the DNA molecule.

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