Question

Important question of natural resources..

class 9th

Answer 1

2-MARKS QUESTIONS
Question.1 The atmosphere acts as a blanket, how ? [SAII – 2012]
Answer. Air is a bad conductor of heat which keeps average temperature of the Earth steady during day and at night. The ozone shield of the atmosphere absorbs most of the harmful radiations coming from Sun.

Question.2 Name four human activities which cause air pollution. [SAII – 2013]
Answer.
(a) Mining activities : Dust released due to mining activities.
(b) Thermal power plants : Fossil fuel burnt in these places causes air pollution.
(c) Firework on festivals : It results in the release of toxic chemicals into air along with hot and toxic gases.
(d) Burning of fossil fuel : In industries, automobiles, domestic purposes etc.

Question.6 Write the composition of soil. On what basis is the type of soil decided ? [SAII – 2013]
Answer. Soil is a mixture. It is composed of small particles of rocks of different sizes, humus (bits of decaying living organism) and various micro-organisms.

 The type of soil is decided by the average size of particles found in it.

Question.7 What are the consequences of global warming ? [SAII -2012]
Answer.

An increase in temperature of earth even by 1 °C may lead to melting of ice on the poles. The melting of ice will result in rise of sea level. Due to rise in sea level,many coastal cities will be flooded or submerged. Increase in temperature of earth, results the changes in weather and may cause excessive raining or drought or extreme hot or cold weather conditions.

Question.8 How are clouds formed ?  [SAII – 2013]
Answer. The water evaporates due to heating Up of water bodies and other biological activities. The air also heats and rises. On rising, it expands and cools to form tiny droplets. These droplets grow bigger, expand and form clouds. The collection of dust and other suspended particles facilitate the process.

Question.9 What is the major source of freshwater in the city/town/village where you live ? [SAII -2011]
Answer. The major sources, of freshwater in the city/town/village is the underground water which is mostly taken out with the help of hand pumps or tube wells. The rivers flowing in the nearby areas, lakes and ponds also serve as the source of freshwater.

Question.10 What is soil erosion ? [SAII -2012]
Answer. The removal of topsoil which is rich in humus and nutrients by flowing water or wind is known as soil erosion. If this process continues further, then all soil may get washed away and the rocks underneath may get exposed. It may lead to the loss of all valuable resources because nothing grows as such on the rocks.

Question.11 What are the two forms of oxygen found in the atmosphere ? [SAII -2011]
Answer.
(i) Elemental oxygen is normally found in the form of a diatomic molecule (O2) in the lower regions of the atmosphere to the extent of 21%. It is non-poisonous form of oxygen.
(ii) But in the upper reaches of the atmosphere (stratosphere), it occurs in the form of ozone, containing three atoms of oxygen and having the molecular formula O3. It is the poisonous form of oxygen
.


hope this helps you

Answer 2

See the attachment..........