The process by which water from the surface of the earth moves to the atmosphere is evaporation.

95% of the Earth's water is stored in its oceans, from where the water cycle starts. 

86% of global evaporation occurs from the ocean due to its large surface area which directly comes in contact with sun rays and gives maximum vaporisation.

Water exists in liquid form upto  $100^0$C , at 100$^0$C it exists as vapour and at 4$^0$C it exists in solid form  as ice. So water exists in all the states or forms except semisolid, jelly state

Water is a stable compound. Components made up of two or more elements is called a compound. Water is made up of two elements namely hydrogen and oxygen.

Groundwater is mostly used as drinking water source by us. 

Constructing factories and houses involve a large scale of deforestation. Due to deforestation, the soil will not remain intact due to which the water holding capacity of the soil decreases which causes a depletion in the water table. Making of concrete floors and roads do not allow the rainwater to seep through the soil and therefore causes a fall in the level of the water table.

Water molecular formula is $H _2O$. Water has 2 hydrogen and one oxygen atom. So it produces hydrogen and oxygen in the ratio 2:1.

Well water is an example of underground water. A water well is an excavation or structure created in the ground by digging, driving and or drilling to access ground water in underground aquifers. The well water is drawn by a pump or using containers such as buckets that are raised mechanically or by hand.

Rainfall pattern will depend on number of water bodies in an area, as there will be large water bodies, (ocean, river) the rate of evaporation would be high, which will help to cause rain in the area.