Indicator of water pollution:
1.  E. Coli
2.  Chlorella
3.  Beggiatoa
4.  Ulothrix

Sewage purification is performed by:
1.  Microbes
2.  Fertilisers
3.  Antibiotics
4.  Antiseptics

Concentration of DDT is highest in:
1.  Primary consumer
2.  Producers
3.  Top consumer
4.  Decomposers

Large-scale death of fish occurs in:
1.  Saline lake
2.  Oligotrophic lake
3.  Eutrophic lake
4.  Shallow lake

The main reason for water bloom in rivers, lakes, sea, etc. is:
1.  Brown algae and green algae
2.  Cyanobacteria and dinoflagellates
3.  Eicchornia
4.  Fishes

Maximum DDT is present in birds feeding on:
1.  Fishes
2.  Meat
3.  Insects
4.  Seeds

The shell of an egg in a bird becomes thin (not properly formed) due to the pollution of pesticides. This is due to interference in the activity of:
1.  Ca ATPase
2.  Mg ATPase
3.  Calmodulin
4.  None

Which of the following is absent in polluted water:

1. Hydrilla

2. Water hyacinth

3. Larva of stone fly

4. Blue-green algae

Fluoride pollution mainly affects:

1. Brain

2. Heart

3. Teeth

4. Kidney