Cigarette smoke contains the carcinogen

Options

A. N-nitrosodimethylene
B. Aflatoxin
C. Vinyl chloride
D. Diethylstilbestrol

Answer

### Step-by-Step Solution:

1. **Understanding Carcinogens**:
- Carcinogens are substances that can lead to cancer by altering cellular metabolism or directly damaging DNA.

2. **Identifying the Options**:
- The options provided are:
- N-nitrosodimethylmethylene
- Aflatoxin
- Vinyl chloride
- Diethyl ethyl

3. **Analyzing Each Option**:
- **N-nitrosodimethylmethylene**: This is known to be a carcinogenic agent found in cigarette smoke and is associated with various types of cancer, including lung, liver, and throat cancer.
- **Aflatoxin**: While it is a carcinogen, it is primarily associated with moldy grains and nuts, not specifically with cigarette smoke.
- **Vinyl chloride**: This is a carcinogen linked to certain types of cancer, but it is not a primary component of cigarette smoke.
- **Diethyl ethyl**: This does not have a strong association with carcinogenic properties in the context of cigarette smoke.

4. **Conclusion**:
- Based on the analysis, the correct answer is **N-nitrosodimethylmethylene**, as it is directly associated with cigarette smoke and its carcinogenic effects.

### Final Answer:
The carcinogen present in cigarette smoke is **N-nitrosodimethylmethylene**.

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