Trinitrotoluene is used as:

1. a preservative
2. a fertiliser
3. a fuel
4. an explosive

Mortar is used as:

1. a plastic material
2. a building material
3. an insecticide
4. a medicine

Urea is an important:

1. fuel
2. preservative
3. fertiliser
4. food item

The chemicals prescribed by a doctor in treatment of infectious diseases are called:

1. antigens
2. preservatives
3. antibiotics
4. fertilisers