Parasite is an organism which always lives inside the body of other organism and may kill it.

Host is an organism which provides food to another organism.

Amensalism is a relationship in which one species is benefited where as the other is unaffected

Predator is an organism that catches and kills other organism for food.

B

A

D

C

Uttarakhand

Assam

Uttar Pradesh

Himachal Pradesh

The river water is still suitable for drinking as impurities are only about 0.1%

Small animals like rats will die after drinking river water

The increased microbial activity releases micro-nutrients such as iron

The increased microbial activity uses up dissolved oxygen