Which of the following nitrogenous bases are common for both RNA and DNA?

Options

A. C, G, A
B. G, A, U
C. T, A, C
D. U, A, C

Answer

To determine which nitrogenous bases are common to both RNA and DNA, we can follow these steps:

### Step 1: Understand the Structure of DNA and RNA
- DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) are both nucleic acids that contain nitrogenous bases.
- The nitrogenous bases are categorized into two groups: purines and pyrimidines.

### Step 2: Identify the Nitrogenous Bases in DNA
- The nitrogenous bases in DNA are:
- Purines: Adenine (A) and Guanine (G)
- Pyrimidines: Cytosine (C) and Thymine (T)

### Step 3: Identify the Nitrogenous Bases in RNA
- The nitrogenous bases in RNA are:
- Purines: Adenine (A) and Guanine (G)
- Pyrimidines: Cytosine (C) and Uracil (U) (instead of Thymine)

### Step 4: Compare the Bases in DNA and RNA
- Common bases between DNA and RNA:
- Adenine (A)
- Guanine (G)
- Cytosine (C)

### Step 5: Identify the Bases that are Not Common
- Thymine (T) is present in DNA but not in RNA.
- Uracil (U) is present in RNA but not in DNA.

### Conclusion
- The nitrogenous bases that are common to both RNA and DNA are Adenine (A), Guanine (G), and Cytosine (C).

### Final Answer
The common nitrogenous bases for both RNA and DNA are: **Adenine (A), Guanine (G), and Cytosine (C)**.

---