Temperature variation in Pacific ocean in present time is called:
1.  Cyclone effect
2.  El Nino effect
3.  Greenhouse effect
4.  Gaudikov's effect

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

Most stable pesticides:
1.  Organophosphates
2.  Organochlorines
3.  Bordeaux mixture
4.  Azaderectnin

Best economic method to harvest solar energy:
1.  Solar cell
2.  Energy plantation
3.  Cultivation of sugar cane then energy obtain by burning it
4.  Solar cooker

In 1984, the Bhopal gas tragedy took place because methyl isocyanate:

1. Reacted with ammonia

2. Reacted with CO₂

3. Reacted with water

4. Reacted with DDT

Bhopal gas tragedy is related to:
1.  Methane
2.  Carbon monoxide
3.  Methyl Isocyanate (MIC)
4.  $S{O}_2$

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

Recently Govt. of India has allowed the mixing of alcohol in petrol. What is the amount of alcohol permitted for mixing in petrol:

1. 10–15%

2. 10%

3. 5%

4. 2.5%

Which of the following is a secondary pollutant:
1. PAN
2. CO
3. $N{O}_2$
4. $S{O}_2$

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