Select the incorrect statements :-

Options

A. In 1983, an American company Elililly produced chain -A and chain B separately by introducing two DNA sequences in plasmid of E. Coli.
B. Insulin consists of chains two -A and chain-B which are linked to eah other by disulphide bond
C. In world, about 20 recombinant therapeutics have been approved for human use, of which about 10 are being marketed in Indian at present
D. Earlier, insulin was isolated from pancreas of the slaughtered cattele and pigs

Answer

To solve the question of selecting the incorrect statements regarding insulin production and recombinant therapeutics, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1**: "In 1983, an American company Alilili produced chain A and chain B separately by introducing two DNA sequences in the plasmid of E. coli."
- This statement is **correct**. Alilili indeed produced the two chains of insulin (A and B) by introducing the respective DNA sequences into the plasmid of E. coli.

2. **Statement 2**: "Insulin consists of two chains A and B which are linked to each other by disulfide bonds."
- This statement is also **correct**. Insulin is composed of two polypeptide chains (A and B) that are connected by disulfide bonds.

3. **Statement 3**: "In the world, about 20 recombinant therapeutics have been approved for human use, of which 10 are being marketed in India at present."
- This statement is **incorrect**. The correct information is that approximately 30 recombinant therapeutics have been approved for human use globally, and 12 of these are marketed in India.

4. **Statement 4**: "Earlier, insulin was isolated from the pancreas of slaughtered cattle and pigs."
- This statement is **correct**. Before the advent of recombinant DNA technology, insulin was indeed extracted from the pancreases of slaughtered animals such as cattle and pigs.

### Conclusion:
The incorrect statement is **Statement 3**.

### Final Answer:
- The incorrect statement is **Statement 3**.