Water helps in regulating the temperature of the body. Sweat forms during summer so evaporation of sweat helps in cooling of body

Upto 70% of our body is made by water.

The ocean water contains high concentration of different salts rendering the water salty making it unfit for use.

When water vapours come together in the air, they become heavy and in more cool temperature, they freeze in the air and start falling.

These processes are evaporation and transpiration.

(a) Yes, water exists in three phases:
(i) Water which is liquid phase.
(ii) Ice represents solid phase.
(iii) Steam is the gas phase.
(b) When ice is kept at room temperature, it melts, loosing its solid phase and entering liquid phase by turning into water.
(c) Vineet is an observant and curious person. He asks questions to satisfy his curiosity and readily accepts concepts.

If we use water extensively for various purposes, the level of water table goes down which will result in shortage of water in future.

Areas covered with concrete affect the availability of groundwater because concrete reduces the seepage of rainwater into the ground which leads to reduction in the availability of groundwater.

The water in shallow ponds evaporates in summer. This process is fast in hot areas leading to shortage of water in the pond and sometimes no water in ponds leads to the death of aquatic animals like fish.

Wet clothes placed on a clothes line dry after sometime because water present in wet clothes is converted into water vapour and released in atmosphere due to evaporation which leaves them dry.

The common salt dissolved in half a cup of water can be recovered by removing the water from the salt solution. This can be done by heating the solution on a gas stove or keeping it under the sun in a plate for few hours. Due to evaporation of water in both the processes, we will get the salt back.

The process by which land water returns back to a sea or an ocean is as follows:
(i) Snow/Rain falling on the mountains melts into water that flows down in the form of streams and rivers.
(ii) A part of the rainwater gets absorbed into the ground and rest also flow in the form of stream or rivers.
(iii) The river water after passing through various regions ultimately reaches into a sea or an ocean