Suggest a suitable word for each of the following statements.
(a) Chemicals added to food to prevent the growth of the microorganism.
(b) Nitrogen-fixing micro-organisms present in the root nodules of legumes.
(c) Agents which spread pathogens from one place to another.
(d) Chemicals which kill or stop the growth of pathogens.
(a) Preservatives
Preservatives are the chemicals that control microbial growth and helps in prevents of spoilage of food. Examples – Sodium benzoate, potassium metabisulphite etc.
(b) Rhizobium
Rhizobium is a nitrogen-fixing bacteria present in nodules of roots of leguminous plants which converts atmosphere nitrogen to nitrites or nitrates that is required for plants.
(c) Carrier/Vector
Vector carry pathogens for example – female Anopheles mosquito carries Plasmodium which causes malaria.
(d) Antibiotics
Antibiotics are the chemicals which destroy or inhibit the growth of disease-causing microbes and are produced by certain bacteria or fungi.