Which substance is tested in case of toxicity/safety testing using transgenic animals?

Options

A. Chemicals
B. Pathogen
C. The amount of DNA in the cell
D. The amount of tolerable radiation levels of an organism

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the substance that is tested for toxicity and safety using transgenic animals.

2. **Identifying the Options**: The options provided are:
- a) Chemicals
- b) Pathogen
- c) The amount of DNA in the cell
- d) The amount of tolerable radiation level of an organism

3. **Defining Toxicity and Safety Testing**: Toxicity and safety testing is primarily concerned with evaluating the harmful effects of substances, particularly chemicals and drugs, on living organisms.

4. **Role of Transgenic Animals**: Transgenic animals are genetically modified to express certain genes that make them more sensitive to toxic substances. This allows researchers to observe and measure the effects of these substances more accurately.

5. **Analyzing Each Option**:
- **Option a (Chemicals)**: This is the correct answer. Toxicity testing is primarily conducted on chemicals and drugs to assess their safety and potential side effects.
- **Option b (Pathogen)**: This is incorrect. Pathogens are not the primary focus of toxicity testing.
- **Option c (The amount of DNA in the cell)**: This is also incorrect as it does not relate to toxicity testing.
- **Option d (The amount of tolerable radiation level of an organism)**: This is not relevant to toxicity testing.

6. **Conclusion**: Based on the analysis, the substance tested in toxicity and safety testing using transgenic animals is **chemicals**.

**Final Answer**: Chemicals

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