Concept:Evapo-transpiration is a natural part of the water cycle, not a source of air pollution.
Explanation:Air pollution occurs when harmful substances enter the atmosphere.
Fumes from motor vehicles release pollutants like carbon monoxide.
Factories discharge gases such as sulfur dioxide into the air.
Volcanic eruptions emit ash and gases that pollute the atmosphere.
Evapo-transpiration only releases water vapour, which is natural and harmless.
Therefore, evapo-transpiration does not cause air pollution.
Answer:A. evapo-transpiration