Biological mangification occurs in case of

Options

A. Organochlorine insecticides
B. Organophosphate pesticides
C. Plants and animals in ecosystem with abundant resources
D. Photography.

Answer

### Step-by-Step Solution:

1. **Understanding Biological Magnification**:
- Biological magnification, also known as biomagnification, refers to the process where certain substances, such as pesticides or heavy metals, increase in concentration as they move up the food chain. This means that organisms at higher trophic levels have a higher concentration of these substances compared to those at lower levels.

2. **Identifying the Substances**:
- The question lists several options: organochlorine insecticides, organophosphate pesticides, plants and animals in ecosystems with abundant resources, and photography. We need to identify which of these substances is known for causing biological magnification.

3. **Analyzing the Options**:
- **Organochlorine Insecticides**: These are synthetic chemicals used for pest control. They are known for their persistence in the environment and ability to accumulate in the fatty tissues of living organisms.
- **Organophosphate Pesticides**: These are also used for pest control but are generally less persistent in the environment compared to organochlorines and do not typically cause significant biomagnification.
- **Plants and Animals in Ecosystems**: While they are part of the food chain, they do not directly cause biological magnification.
- **Photography**: This option is unrelated to biological magnification.

4. **Conclusion**:
- Based on the analysis, organochlorine insecticides are the correct answer because they are known to accumulate in the bodies of organisms and can lead to higher concentrations at higher trophic levels, thus causing biological magnification.

5. **Final Answer**:
- Biological magnification occurs in the case of **organochlorine insecticides**.