Biofertilisers are organisms that enrich the ____ quality of the soil.

[Microbes-in-Human-Welfare] [class-xii ]

• Water holding
• Nutrient
• Physical
• Chemical
Correct Option: B  [ Nutrient ]

Remark: Biofertilisers are organisms that enrich the nutrient quality of the soil.

Cyanobacteria are autotrophic microbes that can fix atmospheric ____.

[Microbes-in-Human-Welfare] [class-xii ]

• Oxygen
• Carbon
• Nitrogen
• Sulfur
Correct Option: C  [ Nitrogen ]

Remark: Cyanobacteria... many of which can fix atmospheric nitrogen.

The overall goal of using biofertilisers is to reduce dependence on ____ fertilisers.

[Microbes-in-Human-Welfare] [class-xii ]

• Organic
• Chemical
• Natural
• Manure
Correct Option: B  [ Chemical ]

Remark: Farmers use these regularly in their fields to replenish soil nutrients and to reduce dependence on chemical fertilisers.

The virus shown in Figure 8.2(a) is a ____.

[Microbes-in-Human-Welfare] [class-xii ]

• Adenovirus
• Bacteriophage
• TMV
• Prion
Correct Option: B  [ Bacteriophage ]

Remark: Figure 8.2 (a) shows a bacteriophage.

The microbial cultures grown on nutritive media are useful for studies on ____.

[Microbes-in-Human-Welfare] [class-xii ]

• Macroscopic organisms
• Micro-organisms
• Viral replication
• Chemical synthesis
Correct Option: B  [ Micro-organisms ]

Remark: Such cultures are useful in studies on micro-organisms.