Which one of the following is a pesticide?

1. benzoic acid
2. aldrin
3. sugar
4. gun powder

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