NEET Biology Class 9 Chapter 6 Natural Resources Long Question And Answers

Natural Resources Long Answer Questions

Directions: Give an answer in four to five sentences.

Question 1. How is energy flux related to carbon oxidation and reduction reactions?
Answer:

Most energy transformations in nature are associated with biochemical oxidation and reduction of carbon, oxygen, nitrogen, phosphorus, and sulfur. The oxidation of the carbon in carbohydrates in respiration releases energy whereas the reduction of carbon in photosynthesis requires the energy input from the sun. The gain of energy in photosynthesis and the subsequent use of that energy in respiration is the fundamental energy flow of nature

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Question 2. How might the oceans serve as a sink for carbon dioxide?
Answer: The ocean’s ability to dissolve carbon dioxide is related in part to the dynamics of biogenic carbonates in the water. When carbon dioxide dissolves in water, it forms carbonic acid), which readily dissociates into bicarbonate and carbonate ions.

When carbon dioxide is removed from ocean surface waters by photosynthesis, the equilibrium between carbon dioxide, bicarbonate, and carbonate changes, resulting in the formation and precipitation of calcium carbonate. This creates a sink for carbon dioxide

NEET Biology Class 9 Natural Resources Long Questions

Question 3. Explain the process of soil formation.
Answer:

Soil is formed through two processes weathering and humifiation.

Weathering: It is the pulverisation of rocks of breaking of rocks into fid particles. There are three types of weathering physical chemical and biological. Sun, water, wind and living organisms perform them.

1. Sun. It causes the expansion of rocks by heating. Cooling causes their contraction at different parts differently. Uneven expansion and contraction produce cracks leading to fragmentation or rocks.
   1. Certain rock components can pick up and lose moisture. They undergo swelling and contraction resulting in fragmentation of rocks.
   2. Frost Action is caused by water seeping in cracks which swell up and exert great pressure if it freezes due to low temperature and undergoes fragmentation.
2. Dust and fie sand carried by wind cause abrasion of the rock surface when the wind strikes the same.
3. Lichens secrete chemicals to dissolve minerals
4. From the rock surface and produces crevices where dust collects. Mosses grow there and cause deepening of crevices. Roots of short-lived plants widen these cracks. Roots of larger plants cause fragmentation of rocks by entering the cracks and growing in size.
   • Partially decomposed organic matter or humus mixes with weathered rock particles to form soil called humiliation. Humus helps in the formation of soil crumbs which are essential for maintaining proper hydration and aeration of soil.

The different causes of water pollution are :

Question 4. What are the causes of water pollution? Discuss how you can contribute to reducing water pollution.
Answer:

1. Domestic sewage and municipal water released directly into waterbodies
2. Untreated industrial waste released into waterbodies.
3. Fertilisers, detergents and biocides reach the waterbodies through drains and rain water.
4. Oil leakage from oil pipelines or from oil tankers into sea.
5. Waste from atomic reactors containing radioactive isotopes is thrown into rivers and seas.
6. Hot water from factories and power plants is released into waterbodies before cooling (thermal pollution.)
7. Eutrophication is caused due to decomposition of organic wastes thrown into waterbodies.

Natural Resources NEET Long Questions and Answers

The following measures can be taken to check water pollution :

1. Treatment of sewage water before being discharged into water resources.
2. Treatment of industrial effluents before being discharged into the river.
3. Preventing toxic substances and radioactive substances from being thrown in waterbodies.
4. Hot water from power plants and factories should be discharged into waterbodies after cooling.
5. Lesser use of fertilisers and biocides.
6. Washing of cloth should be avoided near water-bodies.
7. Dead animals and decaying plants should not be thrown into water bodies.
8. The government should pass laws to prevent water pollution

Detailed Answers for Natural Resources NEET Exam Preparation

Question 5. Carbon dioxide is necessary for plants. Why do we consider it as a pollutant?
Answer:

• It is true that CO₂ is necessary for plants as they need it to synthesise carbohydrates during photosynthesis, but an excessive amount of CO₂ (more than normal concentration) in the atmosphere becomes harmful to living organisms and hence is considered as pollutant.
• The CO₂ is formed inside the body of living organisms as a result of cellular oxidative metabolism. It diffuses out of the body through diffusion. Its excess amount inside the body is harmful.
• Moreover, an excessive amount of CO₂ is causing global warming (greenhouse effect) by forming an envelope around the earth which prevents heat from the earth’s surface from escaping into the atmosphere.

Question 6. How do fossil fuels cause air pollution?
Answer:

• Due to the burning of fossil fuels, like coal and petroleum, oxides of sulphur and nitrogen (SO₂, SO₃, NO₂) are released in the air and act as pollutants and cause respiratory disorders like asthma, bronchitis, pneumonia, lung cancer, etc.
• When the amount of SO₂ and NO₂ increases in the atmosphere, they combine with rainwater to form sulphuric acid ( H₂SO₄) and nitric acid ( HNO₃). When this acid water falls on the earth as rain, it is termed acid rain.
• Acid rain not only decreases soil fertility but affects the animal and human life in several ways.
• Suspended particles in the atmosphere may increase which reduces the visibility. Incomplete combustion of fossil fuel causes the release of CO in the air which is called carbon monoxide poisoning

Natural Resources Class 9 NCERT Long Questions Bank

Question 7. Explain the water cycle with a diagram.
Answer:

1. Water from different water bodies gets evaporated due to the sun’s heat. Plants also loose water during transpiration.
2. The hot air rises up with this water vapour.
3. Water vapour condenses to form big water droplets and clouds.
4. Rain water falls from clouds.
5. The rain water re-enters the water bodies. This process in which water evaporates falls on the land as rain and later flows back into the sea, rivers are known as the water cycle.

NEET Biology Natural Resources Important Long Answer Questions

Question 8. Give the existence of carbon.
Answer:

1. Carbon exists in two different forms in nature free and combined form.
2. Free form: It occurs in the elemental form as diamond and graphite.
3. Combined form: It occurs as carbon-dioxide, carbonates and hydrogen carbonate salts in various minerals, it is also present in proteins, carbohydrates fats, nucleic acids and vitamins.

Carbon cycle:

1. Carbon dioxide present in nature is used by plants during photosynthesis to form glucose and carbohydrates.
2. CO₂ dissolves in water to form carbonates which form limestone.
3. Plants contain carbon in the form of glucose, a carbohydrate that is eaten by other animals. Plants and animals can form animals petroleum if submerged under the earth and plants form coal. But they get decomposed after dying they releaseCO₂back to the atmosphere by decomposition (dead) and respiration (living)

Question 9. Explain the biosphere.
Answer:

1. Biosphere: It consists of the sphere where life exists. Life can exist if all the spheres given below exist.
2. Lithosphere: The crust of the earth also called as land which forms the upper layer of the earth i.e.-soil. The soil provides all the nutrients for all organisms.
3. Hydrosphere: Water available in various forms on the Earth is called hydrosphere. Water exists in solid ice, liquid water and gaseous water vapour forms. It is used by all life forms for their survival.

Water helps in the transportation of nutrients, dissolves nutrients and minerals in it, and makes it available for plants.

Atmosphere: The atmosphere consists of air with different gases present in it like O₂, N₂, CO₂ other gases. Ozone present in the stratosphere helps the various gases present in the atmosphere and is useful for combustion (O₂) respiration (O₂), Photosynthesis (O₂) etc

Best Long Questions for Class 9 Biology Natural Resources

Question 10. Explain the nitrogen cycle in nature and defie all the terms involved in it.
Answer:

Terms involved in the nitrogen cycle are

1. Nitrogen fixation: Plants cannot use free nitrogen present in the air. This nitrogen molecule is converted into nitrates and nitrites which can be taken up and used to make the required molecule. This is called nitrogen fixation which can be done by the bacteria that live in the root nodules of leguminous plants.
   • By physical processes during lightning, high temperatures and pressures are created in the air which converts nitrogen into oxides of nitrogen that dissolve in water and come down along with rain. This is also called nitrification.
2. Ammonifiation: The nitrogen compounds formed are taken by plants to form proteins which are further converted into ammonia.
3. Denitrification:  The nitrates and nitrites of nitrogen are acted upon by another group of microbes example, Pseudomonas bacteria, which convert these compounds into free nitrogen gas.

Nitrogen cycle :

1. Free nitrogen from the atmosphere is converted into nitrates by bacteria or by lightning.
2. Nitrates mix with soil, and are absorbed by the plants to make proteins.
3. The proteins in plants and animals are converted into amino acids and ammonia.
4. Ammonia is converted into nitrates and then these nitrates and nitrites present in soil are acted upon by another group of bacterias called denitrifying bacteria.

The process is called denitrification, nitrates are converted into free nitrogen and are released back into the atmosphere.

Natural Resources Class 9 NEET Descriptive Questions

Question 11. What is the greenhouse effect? Why it is named so?
Answer:

In cold countries where the temperature is low and vegetation does not grow, heat is trapped by glass which allows the heat radiations to enter into the glass but cannot escape out from the glass. These hases are warm where plants grow and are called green-haves.

Greenhouse effects: In nature, there are certain gases in the atmosphere like CO₂, and methane, which allow the sun’s heat to enter the atmosphere but after reflection, these radiations cannot escape out of the atmosphere due to these gases. They help in increasing the temperature and hence called green house effect

Question 12. Explain the following :

1. Eutrophication
2. Biomagnification

Answer:

1. Eutrophication is the process in which excessive growth of algae (commonly called algal bloom) occurs as a result of extra loading of nutrients in the water body. In fact, the presence of sewage and fertilizers (nitrates and phosphates) in polluted water provides a lot of nutrients to the algae (phytoplanktons, etc.) present in the water body. As a result, excessive growth of algae occurs which is termed algal bloom.

• The algae subsequently die and aerobic decomposers become active. They consume rapidly the dissolved oxygen of the water and decompose these dead algae. In the absence of dissolved oxygen, all the aquatic life (including fish) in the water body dies. Thus, eutrophication deprives us of one of our sources of food.

2. The phenomenon of an increase in the concentration of harmful non-biodegradable chemical substances in the body of living organisms at each trophic level of the food chain is called biomagnification or biological magnification. Regular discharge of industrial wastes carrying heavy metals in water bodies has led to the biomagnification of heavy metals such as mercury, cadmium etc. leading to deadly diseases in fish-eating people

NEET Biology Class 9 Chapter 6 Long Answer Type Questions with Solutions

Question 13. Explain the ozone layer, its depletion and the effects of ozone depletion.
Answer:

• The ozone layer, comprising a high concentration of ozone about 18-50 km above in the atmosphere, is commonly called the ozone blanket.
• It is being depleted by air pollutants. Chlorofluorocarbons (CFCs) are synthetic harmful chemicals that are widely used in refrigerators and air conditioners as coolants; in fie extinguishers, in aerosol sprayers, and as propellants.
• These chlorofluorocarbons are air pollutants and are mainly responsible for the depletion of the ozone layer in the atmosphere. When these are released in the air, these harmful chemicals produce ‘active chlorine’ (Cl and CIO radicals) and fluorine in the presence of UV radiation.
• These radicals, through a chain reaction, then destroy the ozone by converting it into oxygen. Due to this, the ozone layer in the upper atmosphere (i.e., stratosphere) becomes thinner. A single chlorine atom can destroy one lakh ozone molecules. Choloroflorocarbons are, therefore, termed major Ozone depleting substances (ODS).
• Other ozone-depleting substances are nitrogen oxides and hydrocarbons. The thinning of the ozone layer allows more ultra violet (UV) radiation to pass through it which then strikes the Earth.

NEET Study Material for Natural Resources with Long Q&A

These cause the following harmful effects on man, animals and plants

1. Skin cancer.
2. Damage to the eyes; also increases the incidence of cataract disease in eyes.
3. Damage to the immune system.
4. Increased embryonic mortality in animals and humans.
5. In plants too, there will be an increased death rate of seedlings, increased incidence of harmful mutations and reduction in yields