What are clouds and how do they form?

Question

which group of clouds produce rain?

Answer 1

A cloud is an aggregate of very small water droplets,ice crystals or a mixture of both,with its base above the earth's surace.

Air contains water;it is usually in the form of water vapour which is an invisible gas.When this humid and warm air rises,it expands and cools.Cold air cannot hold as much water vapour as warm air.So, some of the water vapour condenses upon tiny pieces of dust that are floating in the air and forms a tiny water droplet aroud each dust particle.Millions of such water droplets come together to form clouds.

Answer 2

clouds are tiny droplets of water, because the sun evaporates water, the water becomes lighter until it's light enough to go up as more and more water is evaporated clouds get denser and  denser until this clouds turn dark which are called Nimbus clouds. The tiny droplets of water then combine together to become dense not only droplets of water are combined but also  other factors like dust ,soot, smoke etc. and they become so dense that they fall to the ground.