Process by which we can add or delete certain gene is:

Options

A. Gene therapy
B. Biotechnology
C. Genetic engineering
D. Cytogenetics

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the process through which we can add or delete certain genes. This implies a method that allows for genetic modification.

2. **Identifying the Options**: The options provided include gene therapy, biotechnology, genetic engineering, and cytogenetics. Each of these terms has a specific meaning in the context of genetics.

3. **Analyzing Each Option**:
- **Gene Therapy**: This process involves introducing new DNA into a patient's cells to replace or repair faulty genes. It is primarily used to treat genetic disorders but does not specifically refer to the addition or deletion of genes in a general sense.
- **Biotechnology**: This is a broad field that encompasses various applications of biological systems and organisms. While it includes genetic engineering, it is not limited to gene modification.
- **Genetic Engineering**: This is the specific process that involves the direct manipulation of an organism's genes. It includes techniques to add or delete genes, making it the most relevant option for the question.
- **Cytogenetics**: This field focuses on the study of chromosomes and their structure. It does not specifically deal with the addition or deletion of genes.

4. **Conclusion**: Based on the analysis, the correct answer to the question is **genetic engineering**, as it directly involves the addition and deletion of genes.

**Final Answer**: The process by which we can add or delete certain genes is **genetic engineering**.

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