Lakhmir Singh Solutions for Class 9 Biology Chapter 6 Natural Resources - PDF

1. Write down the composition of the air? 

Ans: 79% of the gas in the air is nitrogen, 20% is oxygen, 1% is carbon dioxide, and there are other additional gases present. Dust particles are also present in the air.

2. How do oxygen and carbon dioxide remain nearly constant in the atmosphere?

Ans: It is through the processes of photosynthesis (in plants) and respiration (in animals) that the atmosphere's concentrations of oxygen and carbon dioxide stay essentially constant. Animals use the oxygen that has been released to breathe, releasing carbon dioxide in the process.

3. How does the average temperature of the earth remain fairly steady?

Ans: The atmosphere largely maintains the Earth's average temperature at a constant level. During the day, it prevents a sharp rise in temperature, and at night, it reduces the rate at which heat escapes into space. It covers the Earth like a blanket as well.

4. How are the winds produced?

Ans: The production of wind results from the sun's heat unevenly heating land masses and sea bodies. A zone of low pressure is created as the air around a landmass warms up, making it lighter and rising. Wind currents are created when air from a high-pressure area exits and moves to a low-pressure area.

5. Set up an experiment to measure the gain and loss of heat by water, sand, and air?

Ans: Place a thermometer inside a closed bottle. For three hours, leave these three in the sun. Check the three containers' temperatures right now. You'll notice that the water is colder than the sand since sand warms up from the sun more quickly than water does. Due to the greenhouse effect, the temperature of a closed bottle will be higher than the temperature of an open bottle.

6. Demonstrate the formation of convective currents.

Ans: When two sections of a liquid are at different temperatures, heat energy can be transmitted by convection. The following experiment can be used to show how convection currents develop.

Required: Beaker, water, potassium permanganate VII, and a Bunsen burner are necessary. A colourful substance called potassium permanganate (VII) dissolves in water when heated.

Procedure: Fill a beaker with water, add potassium permanganate VII, and heat the mixture on a Bunsen burner. The flow of this coloured chemical will be evident as it progressively dissolves in water, demonstrating the development of convective currents.

7. Enumerate the factors that influence the movement of air.

Ans: The factors that influence the movement of air are:

1. Pressure gradient: During land and sea breezes, the air is seen to travel from places of high pressure to areas of low pressure.

2. The Coriolis effect is the deflection of moving air brought on by the earth's rotation.

3. Friction only has an impact on air movement that comes into contact with the Earth. The Coriolis effect has a greater impact than air movement when the air is slowed down by friction.

8. How is rain produced?

Ans: Water flakes that fall from clouds are known as rain. Sun-generated heat transforms water (moisture) from seas, lakes, and rivers into water vapour (gas), which dissipates into the atmosphere. This vapour rises, cools, and transforms into minute droplets of water that eventually form clouds.

9. Set up an experiment to demonstrate the effect of low pressure and particular nuclei over.

Ans: Put 5–10 ml of water into an empty plastic bottle. Shake the bottle vigorously after tightly closing it. 10 minutes in the sun is all it needs. Now, crack open the bottle and let some incense waft within. The bottle must be properly closed. Now, press and release the bottle with your hands for a short period of time.

Observation: When the bottle is exposed to sunshine, the water vapours inside the bottle permeate the air and cause it to evaporate. The air inside the bottle moves to an area of low pressure when the bottle is pushed firmly, creating high internal pressure. The smoke atoms serve as the nuclei that cause the water vapour to condense into minute droplets. when there is pressure. When pressure is released, the air within the bottle gets misty; when pressure is reapplied, the mist goes away.

This happens because the incense stick's smoke particles serve as the centres around which droplets of water vapour condense.

10. Describe the major components of air pollution.

Ans: Sulphur dioxide, nitrogen oxide, carbon monoxide, hydrogen sulphide, hydrogen cyanide, hydrogen fluorides, chlorine, methane, and ammonia are the main pollutants in the air. Vaporised pollutants include unburned hydrocarbons (benzene).

11. Write a brief note on acid rain.

Ans: Acid rain is defined as rain with a high sulphuric acid concentration. Sulphuric acid is created when SO2 and atmospheric water combine, and rain then washes the soil. This is a terrible result of air pollution. Salmon reproduction and plant growth are both negatively impacted. By destroying the stone and bricks, it disintegrates buildings.

12. Explain what smog is. Give its effects

Ans: Smog is a photochemical haze or smoky mist brought on by the sun's UV rays reacting with the atmosphere's principal pollutants. Smog is a result of the accumulation of secondary pollutants such as formaldehyde, aldehydes, and peroxyacetyl nitrate (PAN).

Effects of smog:

1. The visibility has decreased.

2. It is extremely poisonous and suffocating.

13. What are the effects of air pollution on Human beings?

Ans: The following are some of the negative effects of air pollution on people:

1. Asthma, bronchitis, and allergy colds are brought on by airborne suspended particulate matter.

2. Air pollution irritates the lungs, throat, and eyes.

3. Cancer is brought on by vaporized hydrocarbons.

14. Explain the direction of air movement during the day and night in coastal areas.

Ans: Because the land warms up more quickly than the water during the day, the cool air from the sea moves towards the land. Compared to air over the sea, it creates a low-pressure area above the land. As a result, air from the high-pressure region travels to the low-pressure region. Because the land rapidly cools down at night and the pressure of the air above the land increases relative to the pressure of the air above the sea, cool air from the land flows back to the sea during the night. Consequently, there is a reversal of airflow.

15. Give the role of the atmosphere in climatic control.

Ans: The atmosphere of the Earth serves as a protective covering for it. It maintains the Earth's average temperature at a constant level, stops temperature spikes during the day, and slows down heat loss to space at night.

16. Briefly explain the main layers of the atmosphere.

Ans: The top five atmospheric layers are as follows:

1. Troposphere: The troposphere is the lowest air-containing layer that reaches a distance of 8–20 km from the Earth.

2. Stratosphere: The second layer of the atmosphere, it can be seen up to 50 kilometers away from the planet.

3. The third layer of the atmosphere, the mesosphere, is located above the stratosphere.

4. Thermosphere: This fourth layer of the atmosphere can be found up to 100 to 120 kilometers away from the planet.

5. Exosphere: The exosphere is the atmosphere's outermost layer.

17. Explain natural and human-made sources of air pollution.

Ans: Ionising radiation, biocides, pesticides, and photochemical haze are a few examples of natural sources of air pollution.

Industrial pollutants, heavy metals, radioactive materials, car exhaust, and smoke are all examples of man-made air pollution.

18. How are clouds formed?

Ans: A large number of little droplets that are created by the condensation of airborne water vapour combine to form clouds. When dust and other airborne suspended particles serve as a nucleus for water vapour, they condense. The vapours are transformed into minute water droplets by these particles.

19. What is global warming? Give its effects.

Ans: The terms "global warming" or "greenhouse effect" refer to the warming of the atmosphere as a result of the greenhouse gases (carbon dioxide and methane) that trap the heat reflected by the Earth and so raise the Earth's temperature.

Effects of global warming:

• The weather and precipitation patterns on Earth are altered.

• The melting of methane hydrates in polar ice caps and ocean floors causes an increase in methane concentration.

20. Briefly explain the depletion of the ozone layer and its effects.

Ans: A decrease in ozone layer concentration is referred to as ozone layer depletion. It is brought on by ozone-depleting chemicals (ODSs), such as chlorine, nitrogen oxides, methyl bromide, and chlorofluorocarbons (CFCs).

Effects of the ozone layer's thinning include:

• Excessive UV radiation exposure leads to skin cancer.

• It impairs the immune system and the eyes.

• It has an impact on plants, lowering their crop output.

Importance of Lakhmir Singh Class 9 Biology Chapter 6 Natural Resources

If we compare all the other planets with earth, we will find out why life exists on this planet. We will find out that our plant is very caring as it offers the perfect combination of gases to breathe, protects us from harmful sun rays, and also offers a plethora of natural resources to use and sustain.

Thus, the solutions will explain what lithosphere and atmosphere are and what they offer for survival. The chapter will also describe what a hydrosphere is and what different water sources we have. The part of the earth that comprises living organisms is called the biosphere.

On progressing further, this chapter will explain what air and its components are. It will describe how clouds form and distribute water throughout the land. Students will also learn the different uses of water. If you refer to the Biology notes for Class 9 Chapter 6, you will understand the concepts easily. This chapter will explain the different types of soil and their features.

This chapter is important in the ICSE Class 9 Biology syllabus as it explains different types of pollution and their ill effects on the environment. Hence, studying this chapter will not only add knowledge but will also help students score more in the exams.

Benefits of Lakhmir Singh Natural Resources Class 9 exercise solutions

• These solutions have been framed following the latest syllabus of Lakhmir Singh Class 9 Biology Chapter 6. It will help you to understand the meaning of the questions included in the exercises and write the relevant answer accurately.

• The chapter is explained precisely in the notes. You will be able to revise and write answers to fundamental questions such as what are Natural Resources Class 9 Chapter 6. Framing answers will not be a problem when you follow the solutions.

• You can now easily resolve doubts on your own by using the solutions and notes for this chapter.

• Find out your preparation level by practising the Natural Resources Class 9 questions and answers and check where you need to study more in this chapter.

Download Lakhmir Singh Class 9 Biology Chapter 6 Natural Resources Solutions PDF

You can now download the free PDF version of the notes and Natural Resources Class 9 Exercise Solutions. Store the file on your computer and access it according to your study schedule. Follow the answering formats in these solutions and learn how to accurately answer the fundamental questions to score more in the exams.