The genes causing cancer are

Options

A. structural genes
B. expressor genes
C. oncogenes
D. regulatory genes

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the specific type of genes that are responsible for causing cancer.

2. **Identifying the Options**: The options provided are:
- Structural genes
- Expressive genes
- Oncogenes
- Regulatory genes

3. **Defining Oncogenes**: Oncogenes are defined as genes that have the potential to cause cancer. When these genes undergo mutations, they can lead to uncontrolled cell proliferation, which is a hallmark of cancer.

4. **Causes of Mutation**: The mutations in oncogenes can be triggered by various factors, including:
- Carcinogens (chemical substances that can lead to cancer)
- Genetic predispositions
- Environmental factors such as UV rays or X-rays
- Oncoviruses (viruses that can cause cancer)

5. **Consequences of Mutation**: Once mutated, oncogenes can lead to uncontrolled cell growth and division, which can result in tumor formation and cancer.

6. **Conclusion**: Based on the information gathered, the correct answer to the question is that the genes causing cancer are known as **oncogenes**.

### Final Answer:
The genes causing cancer are termed **oncogenes**.

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