A lake near a village suffered heavy mortality of fishes within a few days. Consider the

following reasons for this

(1) Lots of urea and phosphate fertilizer were used in the crops in the vicinity.

(2) The area was sprayed with DDT by an aircraft.

(3) The lake water turned green and stinky.

(4) Phytoplankton populations in the lake declined initially thereby greatly reducing

photosynthesis.

Which two of above were the main causes of fish mortality in the lake?

1. 2, 3

2. 3, 4

3. 1, 3

4. 1, 2

According to Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometres) of the air pollutants is responsible for greatest harm to human health?

1. 2.5 or less

2. 1.5 or less

3. 1.0 or less

4. 5.2 or 2.5

Which one of the following is being tried in India as a biofuel substitute for fossil fuels?

1. Jatropha

2. Azadirachta

3. Musa

4. Aegilops

Which one of the following is the correct percentage of the two (out of the total of 4) green-house gases that contribute to the total global warming?

1. CFCs 14%, CH₄ 20%

2. CO₂ 40%, CFCs 30%

3. N₂O 6%, CO₂ 86%

4. CH₄ 20%, N₂O 18%

Which one of the following statements is correct?

1. Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies

2. Both Azotobacter and Rhizobium fix atmospheric nitrogen in root nodules of plants

3. Cyanobacteria such as Anabaena and Nostoc are important mobilizers of phosphates and potassium for plant nutrition in soil

4. At present, it is not possible to grow maize without chemical fertilizers

Which one of the following is being utilized as a source of bio- diesel in the Indian

countryside?

1. Euphorbia

2. Beetroot

3. Sugarcane

4. Pongamia

In which one of the following the BOD (Biochemical Oxygen Demand) of sewage (S),

distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE) have been

arranged in ascending order ?

1. SE < S < PE < DE

2. SE < PE < S < DE

3. PE < S < SE < DE

4. S< DE < PE < SE

In a coal fired power plant electrostatic precipitators are installed to control emission of:-

1. SO₂ 

2. NO_x

3. SPM

4. CO

Which one of the following is not a bioindicator of water pollution?

1. Sludge-worms

2. Blood-worms

3. Stone flies

4. Sewage fungus

The "blue baby' syndrome results from

1. excess of chloride

2. methaemoglobin

3. excess of dissolved oxygen

4. excess of TDS (Total Dissolved Solids)