Question : Oxygen liberated during photosynthesis comes from:

Option 1: Carbon dioxide

Option 2: Water

Option 3: Breakdown of chlorophyll

Option 4: Atmosphere

Question : What is dry ice?

Option 1: Solid Carbon dioxide

Option 2: Solid Nitrogen dioxide

Option 3: Solid Sulphur dioxide

Option 4: Solid water

Question : Which of the following gases is most toxic ?

Option 1: Carbon dioxide

Option 2: Carbon monoxide

Option 3: Sulphur dioxide

Option 4: Chlorine

Question : The liberation of oxygen during photosynthesis is due to

Option 1: Hydrolysis of carbohydrates

Option 2: Photolysis of water

Option 3: Reduction of CO₂

Option 4: Breakdown of chlorophyll

Question : Transboundary pollution ( or ) Acid rain is caused by:

Option 1: Carbon monoxide

Option 2: Carbon dioxide

Option 3: Hydrocarbon

Option 4: Nitrogen oxide and sulphur dioxide