Biological magnification is caused by

Options

A. organo chlorines
B. organophasphates
C. herbicides
D. radioactive substance

Answer

**Step-by-Step Solution:**

1. **Understanding Biological Magnification**: Biological magnification refers to the process where toxic substances, such as heavy metals and certain chemicals, accumulate in organisms at higher trophic levels of a food chain. This means that as you move up the food chain, the concentration of these toxic substances increases.

2. **Identifying the Cause**: The primary substances responsible for biological magnification are persistent organic pollutants (POPs) that are not easily broken down in the environment. These include organochlorines, which are a class of chemicals that include pesticides like DDT.

3. **Characteristics of Organochlorines**: Organochlorines are known for being fat-soluble and persistent in the environment. This means they can accumulate in the fatty tissues of organisms and remain in the ecosystem for a long time without degrading.

4. **Food Chain Dynamics**: In a typical aquatic food chain, small organisms such as zooplankton may ingest these toxic substances from the water. When larger organisms, like fish, consume these smaller organisms, they also accumulate the toxins. As larger predators consume these fish, the concentration of toxins continues to increase at each trophic level.

5. **Conclusion**: Based on the understanding of biological magnification and the characteristics of the substances involved, we can conclude that biological magnification is primarily caused by organochlorines.

**Final Answer**: Biological magnification is caused by organochlorines.

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