Which one of the following statements is not true?

1.	Concentration of dissolved oxygen below 5 ppm is good for the growth of fish.
2.	Clean water would have a BOD value of less than 5 ppm.
3.	Oxides of sulphur, nitrogen, and carbon are the most widespread air pollutant.
4.	pH of drinking water should be between 6.5-8.5.

Which important greenhouse gas, other than carbon dioxide, is being produced from the agricultural fields?

1. Arsine

2. Sulphur dioxide

3. Ammonia

4. Nitrous oxide

Carbon monoxide is a pollutant because it:

1. reacts with oxygen

2. inhibits glycolysis

3. reacts with haemoglobin

4. makes nervous system inactive

Among the following, the one that is not a greenhouse gas is:

1. Sulphur dioxide

2. Nitrous oxide

3. Methane

4. Ozone

Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity?

1. N₂O₅
2. NO₂
3. N₂O
4. NO

The phenomenon in which atmospheric gases trap the heat radiations from the sun near the earth’s surface and keeps it warm is known as-

1. Natural greenhouse effect

2. Tyndall effect

3. Heating effect

4. Joule’s effect

The gas that damages the ozone layer is -

1. CFCs 

2. CO₂

3. CH₄ 

4. SO₂

Biosphere is

(1) In which individual interact to each other

(2) By which life originated

(3) The name of a bird

(4) Organic compound by which life diminishes

Which is not a renewable source

1. Sunlight

2. Coal

3. Water

4. Wind energy

Noosphere is synonyms of

(1) Environment

(2) Atmosphere

(3) Hydrosphere

(4) Stratosphere