Genetic engineering is involved in :
I. Inserting a gene from Bacillus thuringiensis into cotton.
II. Selective breeding to produce cattle with high milk yields .
III . Using herbicides to kill unwanted plants .
IV. Using insecticide to kill insect pests.

Options

A. I ,II and IV
B. II and III
C. I and III
D. Only I

Answer

To determine which of the given options involves genetic engineering, we will analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** Inserting a gene from Bacillus thuringiensis into cotton.

- **Explanation:** This process involves taking a gene from the bacterium Bacillus thuringiensis (Bt) that codes for a protein toxic to certain insects and inserting it into the cotton plant's genome. This is a classic example of genetic engineering, as it modifies the organism's genetic material to produce a desired trait (insect resistance).

**Conclusion:** This statement is **involved in genetic engineering**.

### Step 2: Analyze Statement II
**Statement II:** Selective breeding to produce cattle with high milk yields.

- **Explanation:** Selective breeding is a traditional method of breeding where individuals with desirable traits are chosen to reproduce. This does not involve direct manipulation of an organism's genes at the molecular level, which is the hallmark of genetic engineering.

**Conclusion:** This statement is **not involved in genetic engineering**.

### Step 3: Analyze Statement III
**Statement III:** Using herbicides to kill unwanted plants.

- **Explanation:** The use of herbicides is a method of weed control but does not involve altering the genetic material of the plants or the herbicides themselves. It is a chemical method of pest management rather than a genetic modification.

**Conclusion:** This statement is **not involved in genetic engineering**.

### Step 4: Analyze Statement IV
**Statement IV:** Using insecticide to kill insect pests.

- **Explanation:** Similar to herbicides, using insecticides is a method of pest control. It does not involve genetic modification of the insecticides or the organisms being treated. While Bt toxin (from Statement I) can act as a natural insecticide when genetically engineered into plants, the statement itself does not refer to genetic engineering.

**Conclusion:** This statement is **not involved in genetic engineering**.

### Final Conclusion
After analyzing all statements, only **Statement I** is involved in genetic engineering. Therefore, the correct answer is:

**Answer:** I only.

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