Answer: Option A. ->
:

Each: 1 Mark
Apart from the above mentioned uses, water is used in
a) Irrigation - Water is used for watering crops.
b) Industries -  Water is used for washing and cooling purposes.

Answer: Option A. ->
:

Characteristics of drinking water: 1 Mark
Reasons for undrinkable sea water: 2 Marks
 

The characteristics of drinking water are :

(i) It should be colourless and odourless.

(ii) It should be free from any suspended impurities.

Water in ocean and seas is salty because many salts are dissolved in it. Salt has dehydrating properties, so the more salt water we drink, the more water is lost from our body. As we drink sea water, the water already present in our body is rerouted to help our body dilute the excess of salt.

Answer: Option A. ->
:

Plants release water vapour into the atmosphere through the process of transpiration.

Answer: Option A. ->
:

Entire process: 5 Marks
Water Cycle is the transportation of water from the land to the sky and back. The processes that make up the water cycle are as follows:

● Condensation - It is the process in which water changes from gaseous state to liquid state.

● Infiltration is an important process in which rainwater soaks into the ground.

● Much of the water that returns to earth's surface as precipitation runs off from the surface of the land, and flows down the hill into streams, rivers, ponds and lakes.

● Evaporation - The process where a liquid, in this case, water, changes from its liquid state to gaseous state.

● Rain - When water droplets in a cloud are heavy enough, they come down in the form of rain.

● Transpiration -  Plants release water vapour into the air through the process of transpiration.

Answer: Option A. ->
:
a) 2 Marks
b) 2 Marks
c) 1 Mark
a) The moist air coming out from mouth condenses on the glasses and makes them wet. This makes the cleaning process easy.
b) The cool surface of the cold bottle cools the air around it and the water vapours of the air condense on the surface of the bottle. This is the reason of the water around a bottle of cold water.
c) When air is cooled to the dew point, fog droplets form. When the air temperature is the same as the dew point temperature, condensation occurs on tiny particles floating in the air.

Answer: Option A. ->
:

Definition : 2 Marks
Importance : 3 Marks
Rainwater Harvesting refers to the process where rainwater is gradually gathered and accumulated so that it can be used for agricultural, commercial or domestic purposes.
The importance of developing rainwater harvesting system are as follows:
1. The gathered rainwater can be used for agricultural purposes. The environment may be helped to get rid of the tendency to drought.
2. The requirement of water for feeding the live-stocks can be met.
3. The ever-increasing demand for water can be satisfied.

Answer: Option D. -> Lighting of fire
:
D

Among the given options, except for lighting fire, everything requires water.
Water is a very good fire extinguisher i.e., it puts off the fire rather lighting it. 
Making paper is a water-intensive industrial process.
Plants also require water for survival and growth.
We require water for bathing.

Answer: Option D. -> transpiration
:
D

Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapour and is released to the atmosphere. It is essentially evaporation of water from plant leaves.

Answer: Option B. -> Evaporation
:
B
Wet clothes has water in them. When placed near a heater, the water in the clothes evaporate. This causes the wet clothes to dry up.
Condensation is a reverse process where water vapor converts to liquid water.
In the process of freezing, liquid water converts to solid ice.
The process of boiling also converts liquid water to water vapour. However, this is achieved when a large amount of heat is supplied. An example of boiling is when you heat water on a gas stove.

Answer: Option C. -> Rain water harvesting
:
C
Groundwater is a good source of freshwater. However, increase in the usage of groundwater drops the groundwater level. A way to prevent this is harvesting rainwater.
Rainwater harvesting focusses on collection of rain water instead of allowing it to evaporate into the air. It results in the increase of groundwater level.