What is the basic similarity between dew and fog?

Correct answer: Both form by condensation of water vapour

Correct answer: A. Dew and fog are both products of condensation, meaning water vapour changes into tiny liquid-water droplets when air cools to its dew point or becomes saturated. The important difference is where the droplets are found. Dew forms on cool surfaces such as grass, leaves or objects near the ground. Fog consists of tiny droplets suspended in the air near the Earth's surface, reducing visibility. A is correct because it identifies their common process while allowing for their different locations. B is wrong because both can form in many suitable environments, not only in the Himalayas. C is wrong because liquid-to-gas change is evaporation, the opposite direction. D is wrong because water vapour is the starting material for condensation. Memory cue: dew is condensation on a surface; fog is condensation in the air. The same process occurs in different places.