Question

Which of the following microorganisms is used to prepare biofertilizers?
A. Algae
B. Protozoa
C. Virus
D. None of these

Answer 1

Hint: Biofertilizers are composed of free-living or symbiotic living microbes. These are termed natural or organic fertilizers. Moreover, these microbes are beneficial for the plants and do not harm them.

Complete answer:
Fertilizers are compounds that when applied to plants benefit them by enhancing their quality and yield quantity. Biofertilizers are the mixtures of microbes that are used as fertilizers.
-They are beneficial for the soil as well as plant growth. They fix the atmospheric nitrogen and make it available to plants to be used by them for better growth and yield. Biofertilizers are mainly used in organic farming.
-Many free-living or symbiotic microbes are used in biofertilizers, like bacteria species including Rhizobium, Azotobacter, etc, fungus species like Mycorrhiza, algae-like Blue-green bacteria. -Algae like blue-green algae are widely used as biofertilizers as they are free-living microbes that fix the atmospheric nitrogen for the plants. They are cyanobacteria that prefer wet and marshy lands. But they are not suitable to be used in acidic soils.
-Protozoa are bacteria like single-celled organisms. But they are not bacteria and can be regarded as animal or plant cells. They feed on other microbes and cells. Thus, they are used as biopesticides but not as biofertilizers.
-Viruses are very minute organisms. They are dormant or nonliving particles that when entered a host body becomes active or alive. They usually infect and lyse the cells they enter. They cannot be used as biofertilizers as they cause plant diseases and infections to humans.
Thus, the right answer is option A, i.e., Algae

Note: Chemical fertilizers do promote plant growth but contain toxic chemicals that sometimes harm human health and also decrease soil fertility over time. Thus, organic farming should opt over chemical pesticides or fertilizers in which organic biofertilizers and biopesticides should be used.