Assertion: Uracil is present in DNA.
Reason : DNA undergoes replication.

Options

A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.

Answer

To solve the assertion and reason question, let's break it down step by step:

### Step 1: Analyze the Assertion
The assertion states that "Uracil is present in DNA."
- **Fact Check**: In DNA, the nitrogenous bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Uracil (U) is not one of the bases found in DNA; it is found in RNA instead, where it replaces thymine.
- **Conclusion**: The assertion is **false**.

### Step 2: Analyze the Reason
The reason states that "DNA undergoes replication."
- **Fact Check**: DNA replication is a well-established biological process where DNA makes a copy of itself before cell division. This is essential for growth and reproduction in living organisms.
- **Conclusion**: The reason is **true**.

### Step 3: Determine the Relationship
Now, we need to evaluate the relationship between the assertion and the reason.
- Since the assertion is false and the reason is true, the overall statement that combines both is incorrect.

### Final Conclusion
- The assertion is false, and the reason is true. Therefore, the correct answer is that the assertion does not support the reason.