Mycorrhiza is a symbiotic association between

Answer: (c) Fungi and roots of higher plants

Mycorrhiza is a fungus–root partnership: the fungus brings phosphorus and water, the plant gives sugar.

The idea

The word means “fungus-root”. Fine fungal threads grow around or into a plant’s roots and spread far into the soil, reaching water and minerals the root cannot. The fungus passes these to the plant, above all phosphorus, and gets sugar in return.

Fungal threads spread through the soil → Absorb phosphorus and water → Hand them to the root → Plant gives sugar to the fungus

Why the others are wrong

(a) Bacteria with roots = Rhizobium nodules.

(b) Orchids do rely on mycorrhiza — but with fungi, not algae.

The trap

Rhizobium (bacteria) is the other famous root partner.

Also know

Most land plants have this partnership. Pine seedlings grow poorly without it, and an orchid seed cannot even sprout without its fungus. Mycorrhiza is sold as a biofertiliser.