Which statement is not correct :-

Options

A. Heterochromaric is more densely packed
B. DNA replication takes place in `3' rarr 5'` direction
C. Intron is non coding nature
D. DNA have acidic nature

Answer

To determine which statement is not correct, we will analyze each statement provided in the question.

### Step-by-step Solution:

1. **Analyze the first statement: "Heterochromatin is more densely packed."**
- Heterochromatin refers to the tightly packed form of DNA, which is transcriptionally inactive. This statement is correct because heterochromatin is indeed more densely packed compared to euchromatin, which is less condensed and transcriptionally active.

2. **Analyze the second statement: "Introns are non-coding in nature."**
- Introns are segments of DNA that do not code for proteins. They are spliced out during the process of RNA processing. This statement is also correct as introns are indeed non-coding sequences.

3. **Analyze the third statement: "DNA has acidic nature."**
- DNA contains a phosphate group, which is derived from phosphoric acid. This gives DNA its acidic properties. Therefore, this statement is correct as well.

4. **Analyze the fourth statement: "DNA replication takes place in 3 to 5 prime direction."**
- DNA replication is catalyzed by the enzyme DNA polymerase, which synthesizes new DNA strands in the 5' to 3' direction. This means that the template strand is read in the 3' to 5' direction, but the new strand is synthesized in the 5' to 3' direction. Therefore, this statement is incorrect.

### Conclusion:
The statement that is not correct is: **"DNA replication takes place in 3 to 5 prime direction."**

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