Which of following is/are correct ?
A. gene therapy has been tested on a large number of patients with a wider variety of inherited genetic disorders, and in numerous cases it has produced a complete cure.
B. genetic engineering has been used to mass produce insulin for diabetes.
C. DNA hyridization is the base pairing of DNA from two different sources
D. genetic engineering is a technique of plant breeding.

Options

A. A, B
B. B, C
C. A, B, C
D. A, B, C, D

Answer

To determine which of the statements about biotechnology are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement A**: "Gene therapy has been tested on a large number of patients with a wider variety of inherited genetic disorders, and in numerous cases it has produced a complete cure."
- **Analysis**: Gene therapy has shown promise in treating certain genetic disorders, but it has not been widely tested on a large number of patients for a variety of inherited disorders. While there have been successful cases, it is not accurate to say that it has produced a complete cure in numerous cases. Therefore, this statement is **incorrect**.

2. **Statement B**: "Genetic engineering has been used to mass produce insulin for diabetes."
- **Analysis**: This statement is accurate. Genetic engineering techniques have been successfully employed to produce insulin by inserting the insulin gene into bacteria (like E. coli), which then produces insulin that can be harvested for medical use. Thus, this statement is **correct**.

3. **Statement C**: "DNA hybridization is the base pairing of DNA from two different sources."
- **Analysis**: This statement is correct. DNA hybridization involves the pairing of complementary DNA strands from different sources. When two DNA sequences are complementary, they can hybridize, which is a fundamental technique used in various molecular biology applications. Therefore, this statement is **correct**.

4. **Statement D**: "Genetic engineering is a technique of plant breeding."
- **Analysis**: This statement is misleading. While genetic engineering can be used in plant breeding to introduce specific traits, it is a broader technique that encompasses various applications beyond traditional plant breeding methods. Therefore, this statement is **incorrect**.

### Conclusion:
Based on the analysis:
- **Correct statements**: B and C.
- **Incorrect statements**: A and D.

### Final Answer:
The correct options are **B and C**.