Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

4. All of the above

Explanation:

A bio-fertilizer is a substance which contains living microorganisms which, when applied to seeds, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.

AM stands for Arbuscular mycorrhiza. A mycorrhiza is a symbiotic association

between a fungus and the roots of a vascular plant. In this association, the fungus colonizes the host plant roots, either intracellular as in Arbuscular mycorrhizal fungi or extracellularly as in ectomycorrhizal fungi. They are an important component of soil life and soil chemistry. In the symbiotic associations of plant and fungi, Arbuscular mycorrhiza, which is formed between plants and Glomeromycota fungi, has the widest distribution in nature. AM fungi inhabit a variety of ecosystems including agricultural lands, forests, grasslands, and many stressed environments, and colonize the roots of most plants, including bryophyte, pteridophyte, gymnosperms, and angiosperms.