Water Test - 1

The movement of water from Earth’s surface into rivers, oceans, and seas is known as run-off. The water which evaporates from water bodies is returned to these water bodies by the processes of run-off and precipitation.

The correct answer is A.

Why alternative B is wrong:

Transpiration is the release of water vapor by plants and vegetation into the atmosphere.

Why alternative C is wrong:

Evaporation is the process of transformation of water from liquid state to gaseous state.

Why alternative D is wrong:

Precipitation is the falling of water in the form of rain, snow, fog, hail, etc., from the atmosphere onto Earth’s surface.

Plants contribute to the water content in the air. They do so while breathing out. The process by which they breathe out is called transpiration.

The correct answer is A.

Why alternative B is wrong:

Condensation is the process by which water vapours get converted back to liquid water. It reduces the water content in the air.

Why alternative C is wrong:

Precipitation is the fall of water in the form of rainfall, snow, hail, etc.

Why alternative D is wrong:

Evaporation is the process by which water content is added to air when water bodies are heated. This is not the process by which plants add water to the atmosphere.

Boiling the water helps in killing the microorganisms present in it and makes it suitable for drinking purposes.

Evaporation is the process by which water rises above the ground in the form of vapour. In this process, water changes into vapour by absorbing heat from its surroundings.

Usable form of water is the water that is obtained from rivers, lakes, wells, springs, etc. This water can be used for drinking, washing, agricultural and industrial purposes, etc. However, almost two-third of the water on the surface of the Earth is in the form of unusable water in the oceans and seas. These unusable sources of water on Earth are unlimited. Usable sources of fresh water, that contribute one third of the total water on the Earth, are limited.

Two-third of the Earth’s surface is covered by water and ice. This water is found primarily in the oceans and seas. Oceans are the largest water bodies on the surface of the Earth. Oceans contain the largest quantities of water on the Earth.

Small microorganisms cannot be seen through the naked eye. Water that looks clear and transparent may contain microorganisms and dissolved impurities. These cannot be seen through the naked eye.

Ocean and sea water is very saline. Large amounts of various salts are dissolved in it. Therefore, water from the oceans and seas cannot be used for domestic purposes such as drinking, washing, bathing, irrigation, etc.

Rainfall occurs because of a continuous movement of water called the water cycle. The pollution of water does not affect the processes involved in this cycle. Flooding is related to the overflowing of a water body. It is not related to water pollution. Hence, the increase or decrease in rainfall and floods is not a result of water pollution.

The correct answer is B.

Why alternative A is wrong:

Diseases such as jaundice and cholera are water borne diseases and are caused by polluted water. Thus, an increase in water pollution can lead to an increase in cases of water borne diseases.

Why alternative C is wrong:

Some factories release their chemical waste into water bodies. This leads to an increase in the chemical content in water bodies.

Why alternative D is wrong:

Fertilizers are used to increase the nutrient content of soil. However, when these nutrients reach water bodies, they cause an unusual increase in the biological activity in the water bodies.