Virus depend on host cell machinery for multiplication. They do not possess any mechanism which allows self multiplication.

Dysentery can be caused by both viral or bacterial infection.  

Viruses can multiply in bacterial, plant or animal cells. 

Antibiotics are produced from fungi and bacteria.

The process of introduction of killed or weakened microbe in a healthy body is called vaccination. No vaccination is available for malaria. 

Yeast is a type of fungus used in baking industry for making breads, pastries, and cakes.

Blue green algae are able to fix nitrogen from atmosphere and enrich soil with nitrogen. 

Disease causing microorganisms are called pathogens. 

Influenza is caused by virus. Viruses do not have their own biochemical pathways, but depend on host cell mechanisms for their growth. Thus, antibiotics cannot target viruses.  

Plague spreads by means of insect vectors. Flea is responsible for transmitting plague-causing microorganisms from rats to human beings.

Dengue virus cause dengue fever. It is transmitted from affected person to healthy person by Aedes mosquito. 

Citrus canker is caused by bacteria, which spreads through air. 

Use of insecticides and avoiding collection of water in surroundings will prevent breeding of mosquitoes. As malaria is spread by mosquitoes, these measures will prevent this disease. 

Rust of wheat is caused by fungi and it can spread by means of air or seeds. 

Pea is a leguminous plant. Rhizobium is found in the root nodules of leguminous plants. 

Milk is heated to about 70°C for 15 to 30 seconds and then suddenly chilled and stored. It prevents growth of microbes. It is called pasteurisation.

Aspirin is not an antibiotic drug, thus not derived from microorganisms. 

Antigens play no role in killing or stopping growth of micro-organisms.

Yeast is grown on natural sugars present in grains for commercial preparation of alcohol and wine. 

A worldwide vaccination campaign by WHO against smallpox has lead to its eradication from most parts of the world.