Answer: Shell fish is used as a biological indicator of pollution.
Step-by-step explanation:
The clams, mussels and shellfishes are some of the organism which can be used as a biological indicator of the pollution.
This is so because they have the ability to filter and concentrate the pollutants such as pesticides, and other pollutants in water.
These organisms can be toxic to people as it includes pollutants. This can be a early warning that the nearby water is getting highly polluted.