The pyrimidine bases present in DNA are

Options

A. cytosine and adenine
B. cytosine and guanine
C. cytosine and thymine
D. cytosine and uracil

Answer

To answer the question about the pyrimidine bases present in DNA, we can follow these steps:

### Step 1: Understand the Structure of DNA
DNA, or deoxyribonucleic acid, is a nucleic acid that consists of two strands forming a double helix. It contains four nitrogenous bases.

**Hint:** Remember that DNA is made up of two types of nitrogenous bases: purines and pyrimidines.

### Step 2: Identify the Types of Nitrogenous Bases
The four bases in DNA are classified into two categories:
- **Purines:** Adenine (A) and Guanine (G)
- **Pyrimidines:** Cytosine (C) and Thymine (T)

**Hint:** Purines have a double-ring structure, while pyrimidines have a single-ring structure.

### Step 3: List the Pyrimidine Bases
From the classification, we can identify the pyrimidine bases in DNA:
- Cytosine (C)
- Thymine (T)

**Hint:** Focus on the bases that are not purines; those will be your pyrimidines.

### Step 4: Conclusion
The pyrimidine bases present in DNA are cytosine and thymine.

**Final Answer:** The pyrimidine bases present in DNA are cytosine and thymine.

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