UPSC Prelims 1999 · General Studies
Question 123: Science and Technology
Which one of the following is a useful functional association between fungi and the roots of higher plants?
AnswerThe answer is (d).
Mycorrhiza is a symbiotic association between a fungus and the roots of a higher plant: the fungus helps the plant absorb water and minerals, especially phosphorus, and the plant gives the fungus food. A lichen is a fungus living with an alga, not a root association. Coralloid roots of cycads host cyanobacteria. Remember: mycorrhiza means fungus plus root.
Why each option is right or wrong
- (a) Wrong. Biofertilizer is a general term for microbial inputs, not a fungus-root association.
- (b) Wrong. Coralloid roots are cycad roots that host cyanobacteria.
- (c) Wrong. A lichen is a fungus with an alga, not a root association.
- (d) Right. Mycorrhiza is the useful fungus-root partnership.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1999, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.