Natural Resources Extra Questions and Answers Science Chapter 14
Are you looking for Natural Resources Extra Questions and Answers, if yes? then you the right place. Here we are providing Natural Resources Extra Questions and Answers Class 9 Science Chapter 14.
- One-line questions
Q.1) What is ammonification?
Ans. Ammonification is a process of formation of ammonium from dead plant material by action of soil microorganisms.
Q.2) State the different forms of carbon found on earth?
Ans. Carbon exists as diamond and graphite in the elemental form. Carbon dioxide, carbonates and hydrogen carbonate are compounds in the combined state. Apart from this carbon-containing molecules like proteins, carbohydrates, fats, nucleic acids and vitamins make important life molecules.
Q.3) What is water cycle?
Ans. The complete process which involves evaporation of water, condensation and rainfall and the flow of water back into the river and sea is called as the water-cycle.
Q.4) What are the different constituents of the biosphere?
Ans. Life on earth is mainly possible due to the biosphere which comprises of the atmosphere, the hydrosphere and the lithosphere.
Q.5) How is water vapor formed in the environment?
Ans. Water vapor is formed by the heating of water in rivers, seas etc. Other than this a number of activities of human activities of living organisms.
Q.6) How are holes in ozone layers generated?
Ans. CFCs react with the ozone layer, which lead to depletion of ozone layer leading to formation of holes in the ozone layer.
- Answer in Short (2 marks)
Q.1) State the different forms of oxygen on earth’s surface.
Ans. 1.) Oxygen is found in the elemental, molecular as well as combined state.
2.) Elemental Oxygen forms 21% of the earth’s atmosphere.
3.) Apart from this, oxygen also exists in the combined state in form of carbon dioxide.
4.) Oxides of metals and silicon, carbonate, sulphate, nitrate and other minerals also contain oxygen.
5.) A number of biological molecules like carbohydrates, proteins, nucleic acids and fats (or lipids) also contain oxygen.
6.) It is also occurring as ozone (O3) in the atmosphere
Q.2) Explain the ways in which carbon dioxide is ‘fixed’?
Ans. (I) Plants are mainly responsible for fixing carbon dioxide present on the earth surface
(II) Plants use carbon dioxide and convert it into glucose in the process of photosynthesis.
(III) Thus, process of photosynthesis is mainly responsible for fixing atmospheric carbon dioxide.
(IV) Apart from this, a number of marine organisms, mainly shell fishes like oysters, crabs, prawns and animals utilize dissolved carbonates of sea-water to maketheir hard shells.
Q.3) What is a green house? Explain the greenhouse effect?
Ans.1) Greenhouses are chambers or shelters made of glass, so that atmospheric heat can be trapped inside the greenhouse making its temperature higher than the surrounding.
2) This is a recent agricultural practice which is used to grow plants in winter season.
3) Some gases like carbon dioxide, methane prevents the escape of heat from the Earth’s atmosphere leading to global warming.
4) Hence, increase in carbon dioxide would cause increase in temperature, this is called the greenhouse effect.
Q.4) What happens to the organic nitrogen in the usable form?
Ans. 1.) Plants can utilize organic nitrogen in form of nitrates and nitrites and convert it into amino acids
- These amino acids are then used to make proteins
- Nitrates and nitrites are used in formation of nitrogen containing complex compounds formed from metabolic pathways.
- Once the plants and animals are dead, decomposing bacteria from soil convert these complex proteins back into nitrates and nitrites.
Q.5) Explain briefly the oxygen cycle.
Ans. a.) The oxygen-cycle plays an important role in maintaing the levels of oxygen in the atmosphere.
- The process of combustion, respiration and formation of oxides of nitrogen utilize the atmospheric oxygen.
- Photosynthesis releases oxygen back into the air.
- This is brief outline of the oxygen-cycle.
Q.6) What is ozone? State its properties.
Ans. a.) Ozone is a molecular form of oxygen in the trimolecular (O3) state.
b.) Ozone is a poisonous gas and is quite unstable is present in the atmosphere when quite near to the sea level.
c.) Ozone has a property of absorbing the harmful ultraviolet radiations from the sun.
Q.7) What is soil pollution?
Ans. Soil pollution is the exclusion of beneficial soil components from the soil. Soil fertility is also affected by addition of pollutants killing the diversity of organisms inhabiting the soil, is known as soil pollution.
- Long answer Questions (5 Marks)
Q.1) Describe the process of nitrogen fixation.
Ans. 1.) Nitrogen gas constitutes 78% of the earth’s atmosphere. It is one of the most important nutrients required by living organisms.
2.) However, nitrogen gas is inert and most of the living organisms cannot utilize it.
3.) A group of bacteria, known as nitrogen fixing bacteria in association with dicot plants fix the atmospheric nitrogen into organic forms.
4.) The nitrates and nitrites are the organic form of nitrogen
5.) Nitrogen fixing bacteria can either be in a symbiotic association or may be free living.
6.) Nitrogen fixing bacteria are mainly found in association with roots of legumes like pulses in a specialized structure called root nodule.
7.) Apart from nitrogen fixing bacteria, physical process like lightening can convert atmospheric nitrogen into organic form.
8.) During lightnings, high temperature and pressure of air converts nitrogen into oxide forms and these oxides dissolved in rain water to form nitric and nitrous acids which can be utilized by various living organisms.
Q.2) Describe the effects of air pollution?
Ans. a.) Air pollution is reduction in quality of air due to addition of pollutants to it.
b.) The main source of air pollution is burning of fossil fuels such as coal and petroleum.
c.) Oxides of Nitrogen and Sulphur are the major source of air pollution.
d.) On inhalation these gases cause respiratory problems in living organisms
e.) These oxides also dissolve in rain, producing acid rains
f.) apart from all this, when fossil fuels are burnt in air, they increase the number of suspended particles in air which are known as hydrocarbons.
g.) In winter season, smog is generated which reduces visibility in the surroundings. Smog is a mixture of smoke and fog and is a major indication of air pollution.
h.) Research has shown that breathing polluted air increases chances of allergies, cancer and heart diseases.
Q.3) What is water-pollution? Explain the factors which can cause water pollution?
Ans. Water pollution is reduction in water quality due to addition of pollutants to it.
A number of factors cause water pollution, some of which are listed below:
- Any unwanted constituents when added to a water body lead to its pollution.
- Fertilizers and pesticides are chemicals compounds used in agriculture cause water pollution.
- Other than this effluents from paper-industry, dyes and textile industry contribute to water pollution.
- Other than this, fecal contamination can add disease causing bacteria to waterbodies.
- When the level of Dissolved oxygen in water goes down, aquatic organisms living in water are affected.
- Temperature changes also affect the water bodies. Drastic changes in the temperature affect the breeding in aquatic organisms.
Q.4) What are the factors responsible to make soil?
Ans. The following factors are responsible for soil formation
- The Sun: Heating up of rocks leads to their expansion during the day. On cooling these rocks contract. Due to this uneven heating and cooling which leads to formation of cracks and fissures. This leads to formation of small rocks.
- Water: Water seeps in the cracks of rocks. When this water than freezes, it causes the cracks in the rocks to widen and leads to soil formation. Flowing water also can break the rocks into smaller pieces. This flowing water may carry rock particles. The action of flowing water, as well as rubbing of the rocks against each other leads to formation of smaller soil particles. These small particles are deposited far away from the original parent rock.
- Wind: strong winds, cyclones etc. breaks down the rocks. air currents carry sand and soil in form of dust particles from one place to the other.
- Activities of living organisms also play an important role in the formation of soil. A popular example is lichen that growing on rocks. Lichens release organic chemicals that cause the rock surface to break down. On this thin layer of soil generated small moss can grow.
- MCQ’s
1) Which process is anaerobic in nature?
(a) photosynthesis
(b) Combustion of petrol
(c) Respiration
(d) Nitrogen fixation
2) Which one of the following are event of water cycle?
(a) evaporation, condensation, rainfall
(b) rainfall, photosynthesis, transpiration
(c) transpiration, condensation, evaporation
(d) photosynthesis, transpiration, condensation
3) In the following list which is a greenhouse gas?
(a) Oxygen
b) Methane
c) Nitrogen
d) Ammonia
4) Humus, living organisms and soil particles are part of which soil layer?
a) Top soil
b) Intermediate layer of soil
c) Layer of big rocks
d) Bottom layer of soil
5) Which of the following process does not consume atmospheric oxygen?
(a) burning of fossil fuel
(b) respiration
(c) Photosynthesis
(d) Oxide formation
6.) The surface of the moon has no atmosphere, due to this reason temperature ranges from
(a) -110 to 190° C
(b) 190° C to 110° C
(c) -190° C to 110° C
(d) 110 to 190° C