How many of these statements are correct ?
(i) In transcription , adenosine pairs with uracil.
(ii) Regulation of lac operon by a repressor is referred to as positive regulation .
(iii) The human genome has approximately 50,000 genes.
(iv) DNA fingerprinting utilizes VNTRs and RFLP.

Options

A. Two
B. Three
C. Four
D. One

Answer

To determine how many of the given statements are correct, let's analyze each statement one by one.

### Step 1: Analyze Statement (i)
**Statement (i):** In transcription, adenosine pairs with uracil.

- **Analysis:** In RNA transcription, adenine (A) from the DNA pairs with uracil (U) in the RNA. The statement incorrectly uses "adenosine," which is a nucleoside, instead of "adenine," which is the nucleotide. Therefore, this statement is **incorrect**.

### Step 2: Analyze Statement (ii)
**Statement (ii):** Regulation of lac operon by a repressor is referred to as positive regulation.

- **Analysis:** The lac operon is regulated by a repressor protein that inhibits transcription when lactose is not present. This is known as negative regulation. Therefore, this statement is **incorrect**.

### Step 3: Analyze Statement (iii)
**Statement (iii):** The human genome has approximately 50,000 genes.

- **Analysis:** According to the Human Genome Project, the estimated number of genes in the human genome is approximately 20,500, not 50,000. Therefore, this statement is **incorrect**.

### Step 4: Analyze Statement (iv)
**Statement (iv):** DNA fingerprinting utilizes VNTRs and RFLP.

- **Analysis:** DNA fingerprinting techniques do utilize Variable Number Tandem Repeats (VNTRs) and Restriction Fragment Length Polymorphism (RFLP). Therefore, this statement is **correct**.

### Conclusion
Now, let's summarize the correctness of the statements:
- Statement (i): Incorrect
- Statement (ii): Incorrect
- Statement (iii): Incorrect
- Statement (iv): Correct

Thus, out of the four statements, only **one statement is correct**.

### Final Answer
**Only 1 statement is correct.**

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