The proof for semiconservative mode of DNA replication was First provided by Matthew Meselson and Franklin Stahl. Escherichia coli were the first organism to be used for this experiment and then it was done in with higher organisms such as plants and human cells. The process of DNA replication in terms of energy is a very expensive process. It involves the formation of a replication fork. Given below is a graph showing the percentage of Adenine in two different double stranded DNA.
Helicase helps in:

Options

A. Stabilising the strands
B. Unwinding the helix
C. Formation of primer strand
D. All of them.

Explanation

**Step-by-Step Solution:**

1. **Understanding DNA Replication**: DNA replication is a crucial biological process where a cell makes an identical copy of its DNA. This process is essential for cell division and involves several enzymes.

2. **Role of Helicase**: Helicase is an enzyme that plays a vital role in DNA replication. Its primary function is to unwind the double-stranded DNA helix, separating the two strands to allow each strand to serve as a template for the formation of new complementary strands.

3. **Options Analysis**:
- **Option A: Stabilizing strand** - This is not the primary function of helicase. Other proteins, such as single-strand binding proteins, stabilize the unwound strands.
- **Option B: Unwinding helix** - This is indeed the main role of helicase. It unwinds the DNA double helix to facilitate replication.
- **Option C: Formation of primer strand** - This is the role of another enzyme called primase, not helicase.
- **Option D: All of them** - Since helicase does not stabilize strands or form primer strands, this option is incorrect.

4. **Conclusion**: Based on the analysis, the correct answer is that helicase helps in unwinding the helix (Option B).

**Final Answer**: B. Unwinding helix

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