Which of the following is a mutagen ?
A. lonizing radiations
B. Gamma rays
C. UV rays
D. Nitrous acid

Options

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

Answer

To determine which of the following options is a mutagen, we need to understand what a mutagen is and the types of agents that can cause mutations.

1. **Definition of Mutagen**: A mutagen is an agent that causes changes in the DNA sequence of an organism, leading to mutations. Mutagens can be physical, chemical, or biological agents.

2. **Types of Mutagens**:
- **Physical Mutagens**: These include various forms of radiation that can damage DNA. Examples are ionizing radiation (like X-rays), gamma rays, and ultraviolet (UV) rays.
- **Chemical Mutagens**: These are chemical substances that can alter DNA. An example is nitrous acid, which can cause mutations by modifying DNA bases.

3. **Analyzing the Options**:
- **A. Ionizing radiations**: This is a type of physical mutagen that can cause mutations by breaking DNA strands.
- **B. Gamma rays**: Also a type of physical mutagen, gamma rays are high-energy radiation that can lead to mutations.
- **C. UV rays**: Another physical mutagen, UV rays can cause DNA damage, leading to mutations.
- **D. Nitrous acid**: This is a chemical mutagen that can cause mutations by altering the structure of DNA bases.

4. **Conclusion**: All four options listed (ionizing radiations, gamma rays, UV rays, and nitrous acid) are mutagens. However, if the question is asking for a specific example, any of these options can be considered correct as they all have mutagenic properties.

**Final Answer**: All of the above options (A, B, C, D) are mutagens.

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