- A Mycorrhiza, an association between fungi and plant roots
- B Plasmodium formation occurring during the aggregative phase of slime moulds
- C Heterocyst formation enabling nitrogen fixation in the cyanobacterium Nostoc
- D Conjugation, the process of genetic material exchange between eubacterial cells
Correct answer: A. Mycorrhiza, an association between fungi and plant roots
Explanation: Mycorrhiza is a symbiotic/mutualistic association between fungi and the roots of higher plants. The fungus helps in absorption of water and nutrients, while the plant supplies sugars and organic nutrients.
Concept context
Whittaker's five kingdom system covering Monera, Protista, Fungi, plus viruses, viroids, and lichens. A foundational NEET chapter on how living organisms are grouped.