The pyrimidine bases present in RNA are

Options

A. Cytosine and Thymine
B. Thymine and Uracil
C. Cytosine and Uracil
D. Uracil and Guanine

Answer

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

### Step 1: Understand what pyrimidine bases are
Pyrimidine bases are one of the two types of nitrogenous bases found in nucleic acids (the other type being purines). Pyrimidines are characterized by a single six-membered ring structure containing nitrogen atoms.

**Hint:** Remember that pyrimidines have a simple ring structure, unlike purines which have a double-ring structure.

### Step 2: Identify the pyrimidine bases
The main pyrimidine bases found in nucleic acids are:
- Cytosine (C)
- Thymine (T)
- Uracil (U)

**Hint:** Thymine is typically found in DNA, while uracil replaces thymine in RNA.

### Step 3: Focus on RNA
In RNA, the pyrimidine bases present are cytosine and uracil. Thymine is not found in RNA; it is exclusive to DNA.

**Hint:** When thinking about RNA, remember that uracil takes the place of thymine.

### Step 4: Conclusion
Thus, the pyrimidine bases present in RNA are cytosine and uracil.

**Final Answer:** The pyrimidine bases present in RNA are cytosine (C) and uracil (U).