Nature’s Treasures — NCERT Solutions

Given: Need to enhance green cover in the locality.

Concept used: Green cover refers to the area covered by trees, plants and vegetation. Increasing green cover helps improve air quality, prevent soil erosion and support biodiversity.

List of actions to enhance green cover:

1. Plant trees and saplings: Plant native trees and shrubs in open spaces, parks, roadsides and school grounds. Participate in tree plantation drives.

2. Maintain a kitchen garden: Grow vegetables, herbs and flowering plants at home in pots or in the garden.

3. Avoid cutting trees: Raise awareness in the community about not cutting trees unnecessarily. Report illegal tree-cutting to local authorities.

4. Water plants regularly: Take care of existing plants and trees by watering them, especially during dry seasons, to ensure their survival.

5. Spread awareness: Educate friends, family and neighbours about the importance of trees and green cover through posters, campaigns and social media.

6. Participate in eco-club activities: Join or form an eco-club in school to organise regular plantation drives and nature conservation activities.

7. Compost organic waste: Use kitchen waste to make compost, which can be used as natural fertiliser to help plants grow better.

Conclusion: Each one of us can contribute to increasing the green cover of our locality through small but consistent efforts.

Note: The illustration (img_11) appears to show cooking using firewood/wood fuel based on the context of the chapter discussing fossil fuels and traditional fuels.

(i) What type of energy is being used for cooking?

Answer: The illustration shows cooking using wood (firewood) as fuel, which provides heat energy through burning (combustion).

(If the illustration shows a gas stove, the answer would be: Chemical energy from LPG/Natural gas, converted to heat energy.)

(ii) One benefit and one drawback:

Given: Large-scale cutting of trees (deforestation) affects soil quality.

Explanation:

Cutting down trees on a large scale negatively impacts soil quality in the following ways:

1. Soil erosion: The roots of trees hold the soil particles together and prevent them from being washed away by rain or blown away by wind. When trees are cut, there are no roots to hold the soil, leading to soil erosion. The fertile topsoil is lost.

2. Loss of nutrients: Leaves that fall from trees decompose and decay on the ground, enriching the soil with nutrients and organic matter (humus). Without trees, this natural process stops, making the soil less fertile.

3. Reduced water retention: Tree roots help the soil absorb and retain water. Without trees, the soil loses its ability to hold water, making it dry and infertile.

4. Loss of microorganisms: Forests support a large number of soil microorganisms (bacteria, fungi, earthworms) that keep the soil healthy. Deforestation destroys their habitat, reducing soil quality.

5. Increased surface runoff: Without tree cover, rainwater flows rapidly over the surface instead of seeping into the soil, causing flooding and further washing away the topsoil.

Conclusion: Trees play a vital role in maintaining soil quality. Large-scale deforestation leads to soil erosion, loss of fertility and degradation of the soil, making it unfit for agriculture and plant growth.

Given: Human activities that cause air pollution.

Concept used: Air pollution occurs when harmful substances are added to the air, making it unfit for breathing and harmful to the environment.

Two ways in which human activities pollute the air:

1. Burning of fossil fuels in vehicles and industries:
Vehicles (cars, trucks, buses) burn petrol and diesel, releasing harmful gases such as carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides and unburnt hydrocarbons into the air. Factories and power plants burning coal also release large amounts of smoke, dust and toxic gases, causing severe air pollution.

2. Burning of waste and crop residue:
Burning of garbage, plastic waste and crop stubble (leftover stalks after harvesting) releases thick smoke containing harmful particles and toxic gases into the atmosphere. This is a major cause of air pollution, especially in agricultural regions.

One action to reduce air pollution:
Use of public transport or electric vehicles: Encouraging people to use buses, metro trains or electric vehicles (which produce zero direct emissions) instead of individual petrol/diesel vehicles can significantly reduce the amount of harmful gases released into the air.

Conclusion: By reducing the burning of fossil fuels and switching to cleaner alternatives, we can greatly reduce air pollution and improve air quality.

Given: A family uses — solar panels (electricity), gas stove (cooking), windmill (pumping water).

Situation: No sunlight for a week.

Analysis of each resource:

1. Solar panels — Affected:
Solar panels work by converting sunlight into electricity. If there is no sunlight for a week, the solar panels will not generate any electricity. The family will have no electricity for lighting, fans, charging devices, etc.

2. Gas stove — Not directly affected:
The gas stove uses LPG (Liquefied Petroleum Gas) or natural gas for cooking. This fuel does not depend on sunlight. Therefore, the family will still be able to cook food without any problem.

3. Windmill — Not directly affected by sunlight:
A windmill works using wind energy, not solar energy. If wind is still available, the windmill will continue to pump water from the well. However, if the absence of sunlight is due to heavy cloud cover with no wind, then the windmill may also be affected.

Summary of impact:

Conclusion: The family would face the most difficulty due to the lack of electricity, as solar panels cannot function without sunlight. This shows the importance of having backup energy sources and not depending entirely on a single resource.

Note: The figure (img_12) showing the concept map/blanks cannot be fully seen from the OCR. Based on the chapter content and the given terms, the most appropriate answers for typical blanks in such a concept map are provided below.

Given terms: fossil fuels, forest, air, petroleum, coal, water, non-renewable resource

Likely concept map / fill in the blanks:

1. Air, water and sunlight are examples of renewable natural resources.

2. Petroleum, natural gas and coal are together called fossil fuels.

3. Fossil fuels are an example of a non-renewable resource because they take millions of years to form.

4. Petroleum is used to obtain petrol, diesel and kerosene.

5. Coal is mainly used for the production of electricity.

6. Forest is a renewable natural resource that provides timber, oxygen and habitat for wildlife.

7. Water is a renewable resource that is essential for all forms of life.

Concept used: Fossil fuels (petroleum, coal, natural gas) are non-renewable resources formed from remains of ancient organisms. Air, water and forests are renewable resources.

Topic: Is large-scale felling of trees justified to meet industrial and housing demands?

Brief Report: Is Felling of Trees Justified?

Introduction:
With the growing human population, the demand for wood (for furniture, paper, construction) and land (for housing and industries) has increased greatly. This has led to large-scale cutting of trees, known as deforestation.

Arguments in favour (Why people fell trees):

• Industries need wood as raw material for paper, furniture and construction.
• Growing cities need land for housing, roads and factories.
• Farmers sometimes clear forests for agricultural land.

Arguments against (Why it is NOT justified):

1. Loss of biodiversity: Forests are home to millions of species of plants and animals. Cutting trees destroys their habitat and can lead to extinction of species.
2. Soil erosion: Tree roots hold soil together. Without trees, fertile topsoil is washed away, making land infertile.
3. Climate change: Trees absorb carbon dioxide and release oxygen. Cutting them increases CO₂ in the atmosphere, contributing to global warming.
4. Disruption of water cycle: Forests play a key role in the water cycle. Deforestation reduces rainfall and leads to droughts.
5. Difficult to regrow: It takes hundreds of years to regrow a forest. Once destroyed, it is nearly impossible to restore it fully.

Conclusion:
The large-scale felling of trees is not justified. While we understand the need for development, it must be done in a sustainable manner — by planting new trees for every tree cut (afforestation), using recycled materials, and finding alternatives to wood. We must balance development with conservation to protect our environment for future generations.

'We do not inherit the Earth from our ancestors; we borrow it from our children.'

Topic: Plan to reduce water usage in school.

Plan: 'Save Water, Save Life' — A School Water Conservation Plan

Objective: To reduce water wastage in school and promote responsible use of water.

Steps to implement the plan:

Step 1 — Identify areas of water wastage:

• Conduct a survey of all taps, toilets, water coolers and gardens in the school.
• Note where water is being wasted (leaking taps, taps left open, overflowing tanks, etc.).

Step 2 — Fix leakages and install water-saving devices:

• Report all leaking taps and pipes to the school administration for immediate repair.
• Install sensor-based or push-type taps that automatically stop water flow.

Step 3 — Awareness campaign:

• Put up posters and slogans about water conservation near taps, toilets and water coolers.
• Conduct assembly talks and competitions (essay, poster, quiz) on water conservation.

Step 4 — Rainwater harvesting:

• Install a rainwater harvesting system on the school roof to collect rainwater, which can be used for gardening and cleaning.

Step 5 — Efficient use of water in gardens:

• Use drip irrigation for the school garden instead of flooding it with water.
• Water plants in the early morning or evening to reduce evaporation.

Step 6 — Monitor and review:

• Form a student eco-committee to regularly check taps and report wastage.
• Track monthly water bills to measure improvement.

How it would help the environment:

1. Conserves freshwater: Freshwater is a limited resource. Saving water in school ensures more water is available for other needs.
2. Reduces energy use: Less water pumped means less electricity used, reducing carbon emissions.
3. Protects water bodies: Less wastage means less strain on rivers, lakes and groundwater sources.
4. Creates responsible citizens: Students who learn to save water at school will carry these habits home and into the community.

Conclusion: A well-planned water conservation strategy in school can save thousands of litres of water every year and inspire the entire community to use water responsibly.