Three pyrimidines are thymine, cytosine and .....

Explanation

To answer the question about the three pyrimidines, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: Recognize that the question is about pyrimidines, which are a type of nitrogenous base found in nucleic acids (DNA and RNA).

2. **Identify Known Pyrimidines**: The question provides two pyrimidines: thymine and cytosine.

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