To determine which statement is incorrect regarding primary and secondary metabolites, we can analyze each option step by step:
1. **Understanding Primary Metabolites**:
- Primary metabolites are compounds that are directly involved in the growth and development of organisms. Examples include amino acids, lactic acid, ethyl alcohol, and acetaldehyde.
- **Hint**: Remember that primary metabolites are essential for basic cellular functions and growth.
2. **Understanding Secondary Metabolites**:
- Secondary metabolites are not directly involved in growth but serve other ecological functions. They are produced by organisms and can have various roles, such as defense mechanisms or attracting pollinators. Examples include alkaloids, flavonoids, and antibiotics.
- **Hint**: Secondary metabolites are often involved in interactions with the environment rather than basic life processes.
3. **Analyzing Each Statement**:
- **Statement A**: "Primary metabolites have identifiable functions."
- This statement is correct as primary metabolites are essential for growth and development.
- **Statement B**: "Some secondary metabolites have ecological importance."
- This statement is also correct since secondary metabolites can play roles in ecological interactions, such as pest deterrence.
- **Statement C**: "Secondary metabolites like rubber, drugs, spices, scent, and pigments are useful to human welfare."
- This statement is correct as many secondary metabolites are indeed beneficial to humans.
- **Statement D**: "Secondary metabolites are not found in fungi, microbes, and plants."
- This statement is incorrect. Secondary metabolites are found in all these organisms. For example, flavonoids are derived from plants, antibiotics from microbes, and various compounds from fungi.
4. **Conclusion**:
- The incorrect statement is **Statement D**: "Secondary metabolites are not found in fungi, microbes, and plants."
**Final Answer**: The incorrect statement is D: "Secondary metabolites are not found in fungi, microbes, and plants."
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