Natural Resources

Natural resources are the backbone of development of a country. Which of the following is not a classification of it?

1. Renewable
2. Non renewable
3. Biotic
4. None

Answer

None

Reason — Natural resources can be classified on the basis of two criteria — renewability (Renewable and Non-renewable) and origin (Biotic and Abiotic). Hence, Renewable, Non-renewable, and Biotic are all valid classifications of natural resources. Therefore, none of these options is "not a classification".

Fossil fuels are Non-renewable resources of energy. Coal, Natural gas, Petroleum etc are fossil fuels.

1. True
2. False

Answer

True

Reason — Fossil fuels like coal, natural gas, and petroleum are formed from the remains of plants and animals buried deep under the earth for millions of years. They exist on earth in fairly fixed amounts and the natural process of their replenishment takes millions of years. Hence, they are classified as non-renewable resources.

Statement I: Biotic resources are forest, agriculture, wildlife, fish etc.

Statement II: Abiotic resources are land, water, minerals etc.

1. (I) is correct
2. (II) is correct
3. Both (I) and (II) is correct
4. None of these

Answer

Both (I) and (II) is correct

Reason — Biotic resources include all living elements of the environment such as forest, agriculture, wildlife, and fish. Abiotic resources include all non-living elements of the environment such as land, water, minerals, sunlight, and natural gas. Hence, both statements correctly describe the classification of natural resources on the basis of origin.

Which atmospheric gas is used by plants to make their food by photosynthesis?

1. Oxygen
2. Nitrogen
3. Carbon dioxide
4. Argon

Answer

Carbon dioxide

Reason — Carbon dioxide in the air is essential for photosynthesis in plants. Plants absorb carbon dioxide through their leaves and use it along with sunlight and water to produce food (glucose), releasing oxygen as a by-product. This is why CO₂ is critical for supporting plant growth and the food chain.

Which of the following is not true?

1. 71% of the earth's surface is covered with water
2. 97% of total water on the earth is salty
3. 3% of the total water on the earth is usable
4. Water contains in human body is around 25%

Answer

Water contains in human body is around 25%

Reason — Nearly 71% of the total area of earth is covered with water, of which 97% is salty (found in oceans) and only the remaining 3% is usable freshwater found in glaciers, rivers, lakes, streams, ponds, underground, and in the atmosphere. However, water content in the human body is approximately 60–70%, not 25%. Hence, this statement is not true.

Soil is formed by the decomposition of rocks and mineral. Which is called

1. Weathering
2. Soilination
3. Rocking
4. None

Answer

Weathering

Reason — Soil is formed by the decomposition of rocks and minerals over a long period of time due to the action of wind, water, temperature changes, and biological activity. This natural formation process is called 'weathering'.

Thermal power station uses ............... to generate electricity.

1. Fossil fuels
2. Water
3. Nuclear energy
4. None

Answer

Fossil fuels

Reason — Thermal power stations use fossil fuels like coal, petroleum, and natural gas to generate electricity. The fuel is burnt to produce heat which is used to boil water and make steam. The force of the steam turns turbines that drive generators, producing electricity. Most large power stations operate on this principle.

A nation's economy is closely linked to the abundance and fertility of land.

1. True
2. False

Answer

True

Reason — In our country, nearly 54% of land is used for agriculture. The quantity and quality of soil are very important for a farmer. Vegetables, oils, forage for livestock, fibre, wood, and various agricultural products come from the soil. Thus, a nation's economy is inseparably linked to the fertility and abundance of its soil resources.

Assertion (A): Minerals like phosphorus and potassium are essential for agricultural productivity.

Reasoning (R): They are key components in fertilizers, supporting plant growth and crop yield.

1. A is true but R is false.
2. A is false but R is true.
3. Both A and R are true and R explains A.
4. Both A and R are true but R does not explain A.

Answer

Both A and R are true and R explains A

Reason — Minerals like phosphorus and potassium are essential nutrients required for plant growth and crop yield, making Assertion (A) true. These minerals are key components of NPK fertilizers (Nitrogen, Phosphorus, Potassium) used to improve crop yields, which makes Reasoning (R) true. The reason correctly explains why these minerals are essential for agricultural productivity.

Which of the following scenarios would lead to the depletion of renewable resources?

1. Excessive logging in a forest without replanting trees
2. Using solar energy for household electricity
3. Harvesting rainwater for irrigation
4. Regulating wind turbines for energy generation

Answer

Excessive logging in a forest without replanting trees

Reason — Although forests are renewable resources, they can be depleted when their consumption exceeds the rate of natural replenishment. Excessive logging without replanting destroys the forest faster than it can regenerate, leading to deforestation and depletion. The other options (solar energy, rainwater harvesting, and wind turbines) are sustainable uses of renewable resources that do not lead to depletion.

Why is over-irrigation considered harmful to soil?

1. It increases the soils fertility.
2. It leads to water logging and salinity.
3. It reduces soil temperature.
4. It helps replenish groundwater.

Answer

It leads to water logging and salinity

Reason — Over-irrigation causes excess water to accumulate in the soil, raising the water table and resulting in waterlogging. As water evaporates from the surface, dissolved salts are left behind, leading to salinity. Both conditions damage soil structure, reduce fertility, and harm plant growth.

How does deforestation directly contribute to climate change?

1. By increasing atmospheric nitrogen
2. By increasing carbon dioxide levels due to reduced carbon sequestration
3. By reducing the water cycle
4. By lowering soil fertility

Answer

By increasing carbon dioxide levels due to reduced carbon sequestration

Reason — Trees absorb carbon dioxide from the atmosphere during photosynthesis, acting as natural carbon sinks. Deforestation reduces this carbon sequestration capacity, allowing more CO₂ to accumulate in the atmosphere. Since CO₂ is a major greenhouse gas, its increase directly contributes to global warming and climate change.

What would happen if all non-renewable resources were depleted?

1. Industries would shift to sustainable alternatives.
2. There would be no impact on daily life.
3. The environment would recover faster.
4. Energy production would increase.

Answer

Industries would shift to sustainable alternatives

Reason — If non-renewable resources like coal, petroleum, and natural gas were completely depleted, industries would be forced to shift to alternative or non-conventional sources of energy such as solar, tidal, wind, hydel and nuclear energy. Daily life would be significantly affected, and energy production would not increase.

Which of the following actions contributes to soil conservation?

1. Cutting down trees for farming
2. Practicing crop rotation and planting cover crops
3. Overgrazing by livestock
4. Intensive tillage farming

Answer

Practicing crop rotation and planting cover crops

Reason — Crop rotation maintains soil fertility by alternating crops that demand different nutrients, while cover crops protect the soil from erosion and add organic matter. Both practices preserve soil structure and replenish nutrients naturally. Cutting trees, overgrazing, and intensive tillage all expose the soil to erosion and degradation.

If a country's water table continues to deplete, what long-term impact might this have on its agricultural economy?

1. Increased reliance on groundwater
2. Expansion of rain-fed agriculture
3. Shift towards drought-resistant crops and water-saving techniques
4. Reduction in the demand for agricultural products

Answer

Shift towards drought-resistant crops and water-saving techniques

Reason — As the water table depletes, water for irrigation becomes increasingly scarce. To sustain agriculture under such conditions, farmers will be forced to adopt drought-resistant crops that require less water, along with water-saving techniques like drip and sprinkler irrigation. Relying further on already depleted groundwater is unsustainable in the long term.

What would happen if nitrogen-fixing bacteria were absent in the soil?

1. Plants would grow faster.
2. Nitrogen availability in the soil would decrease, affecting plant growth.
3. Soil fertility would remain unaffected.
4. The oxygen cycle would be disrupted.

Answer

Nitrogen availability in the soil would decrease, affecting plant growth

Reason — Soil contains a wide variety of bacteria, including nitrogen-fixing bacteria, that help convert atmospheric nitrogen into compounds plants can absorb (such as nitrates and ammonium). Without these bacteria, plants would not get usable nitrogen from the soil, severely affecting plant growth and reducing soil fertility.

Why is wind considered a renewable resource?

1. It can be stored for later use.
2. It is continuously replenished by natural processes.
3. It requires fossil fuels to generate energy.
4. It is available only in specific regions.

Answer

It is continuously replenished by natural processes

Reason — Wind is a renewable resource because it is continuously produced by natural processes. The uneven heating of the earth's surface by the sun creates pressure differences that cause air movement (wind). As long as the sun shines, wind will keep being generated, making it inexhaustible.

How does water pollution impact aquatic ecosystems?

1. It increases oxygen levels.
2. It disrupts food chains and reduces biodiversity.
3. It has no effect on aquatic life.
4. It enhances fish population growth.

Answer

It disrupts food chains and reduces biodiversity

Reason — Water pollution contaminates aquatic habitats and harms sensitive species such as fish, plankton, and aquatic plants. Since smaller organisms support larger predators in the food chain, the death of one group disrupts the entire chain. This loss of species reduces overall biodiversity in the ecosystem.

Air is essential for the nitrogen cycle, as nitrogen gas in the atmosphere is directly absorbed and utilized by plants.

1. True
2. False

Answer

False

Reason — Although air is essential for the nitrogen cycle, plants cannot directly absorb atmospheric nitrogen gas. Nitrogen must first be "fixed" — converted into usable forms like nitrates and ammonium — by nitrogen-fixing bacteria in the soil (or by lightning) before plants can use it. Hence, the statement is false.

What is the primary benefit of transitioning to solar energy?

1. It reduces global energy demand.
2. It is costlier but more efficient than fossil fuels.
3. It provides a sustainable and eco-friendly energy source.
4. It has no environmental impact.

Answer

It provides a sustainable and eco-friendly energy source

Reason — Solar energy is renewable, abundant and clean. Unlike fossil fuels, it does not emit greenhouse gases or pollutants during electricity generation. It is continuously replenished by the sun and helps reduce dependence on non-renewable resources.

What do you understand by a natural resource?

Answer

A natural resource is any matter or energy derived from the environment, such as air, water, soil, minerals, plants and wildlife, that is used by living things including humans.

How many kinds of natural resources are available? Name them.

Answer

Natural resources can be classified on the basis of two criteria:

(a) On the basis of Renewability:

1. Renewable resources — include water, forests, sunlight, wind, etc.

2. Non-renewable resources — include fossil fuels (coal, natural gas, petroleum) and minerals.

(b) On the basis of Origin:

1. Biotic resources —include forest, agriculture, wildlife, and fish.

2. Abiotic resources — include land, water, minerals, sunlight, and natural gas.

Differentiate between renewable and non-renewable resources. Give examples of each.

Answer

How can conserving water from different sources, like rivers and groundwater, help in dealing with water scarcity?

Answer

Conserving water from rivers and groundwater is essential to deal with water scarcity in the following ways:

1. Sustains Drinking Water Supply — Conservation ensures that limited freshwater remains available for domestic use.

2. Supports Agriculture — Conserving river water and groundwater ensures better availability of water for irrigation.

3. Maintains Water Table — Rainwater harvesting and reduced groundwater extraction prevent the water table from depleting.

4. Supports Industrial Use — Conservation ensures a steady supply of water for industries.

5. Protects Ecosystems — Rivers and groundwater support aquatic life and surrounding ecosystems. Conservation helps maintain these ecosystems.

How forests help to prevent drought and floods?

Answer

Forests play a vital role in preventing both drought and floods in the following ways:

1. Giant Water Retainers — Forests act as giant water retainers by absorbing rainwater.

2. Gradual Release of Water — They gradually release absorbed water into rivers and streams, helping to maintain water flow during dry periods.

3. Prevention of Runoff — Forest cover reduces the speed of surface runoff, thereby reducing the chances of floods.

4. Soil Conservation — Roots of trees hold the soil firmly and prevent soil erosion and silting of rivers and streams.

5. Regulation of Water Cycle — Trees release water vapour through transpiration, which helps in maintaining the water cycle.

How do renewable energy resources like solar and wind power help in reducing environmental pollution?

Answer

Renewable energy resources like solar and wind power help reduce environmental pollution in the following ways:

1. No Greenhouse Gas Emissions — Solar and wind energy do not release carbon dioxide or other greenhouse gases during electricity generation.

2. No Water Pollution — Solar and wind plants do not release pollutants into water bodies, thereby preserving aquatic ecosystems.

3. Reduce Dependence on Fossil Fuels — By replacing fossil fuels for electricity generation, they help conserve non-renewable resources.

4. Sustainable and Clean — They can be used indefinitely without environmental degradation.

Which are the various layers of soil? How soil is useful in our daily life?

Answer

Layers of Soil: The soil profile has three main layers.

1. Uppermost layer (Top soil) — This layer is rich in humus and contains nutrients essential for plants.
2. Middle layer (Sub soil) — This layer contains minerals like iron oxide.
3. Lowest layer (C-horizon) — This is the bedrock layer composed of large pieces of rock.

Usefulness of Soil in Daily Life:

1. Supports Living Beings — Along with sunlight, air and water, soil supports all living beings on land. Vegetables, oils, forage for livestock, fibre, wood and various agricultural products come from soil.

2. Importance for Farmers — For a farmer, soil is the essence of survival. Productivity of agricultural produce is directly linked with the fertility of soil.

3. Decomposition — Soil contains a wide variety of bacteria, fungi and protozoa, which help in the decomposition of organic matter.

4. Shelter — Soil provides shelter to wildlife and different soil organisms such as earthworms, snails, rabbits, snakes and rats.

5. Reservoir of Water — Due to its porosity and water-holding capacity, soil serves as a reservoir of water and supplies water to plants.

6. Medical Uses — Soil contains minerals and substances with medical properties, which are used in various medicines.

Differentiate between abiotic and biotic natural resources with examples.

Answer

How does solar energy act as a resource?

Answer

Solar energy acts as one of the most important natural resources for human beings in the following ways:

1. Renewable Resource — Solar energy is continuously replenished by the sun and is not likely to be exhausted.

2. Electricity Generation — Solar panels convert sunlight into electricity.

3. Heating and Cooking — Solar water heaters use the sun's heat to provide hot water, and solar cookers use sunlight for cooking.

4. Clean Source of Energy — Solar energy does not produce smoke or harmful gases during use.

5. Reduces Dependence on Fossil Fuels — It helps reduce the use of coal, petroleum and natural gas.

What are the uses of forests?

Answer

Forests are valuable natural resources that provide numerous benefits to mankind and the environment. The various uses of forests are as follows:

1. Source of Wood and Timber — Forests are a major source of wood used in construction.

2. Source of Pure Oxygen — Forests are a major source of pure oxygen, as trees release oxygen during photosynthesis. They are often called the "lungs of the earth."

3. Giant Water Retainers — Forests serve as giant water retainers. They absorb rainfall and gradually release it into rivers.

4. Prevention of Soil Erosion — Forest cover helps in preventing soil from being eroded and silting up of rivers and streams.

5. Source of Livelihood for Tribes — Most of the tribes are directly or indirectly dependent on the forest for their livelihood.

6. Shelter for Wildlife — The trees in the forests are shelters for many animals, insects, birds, etc.

7. Raw Material for Industries — Forests provide raw materials to various industries like pulp and paper, rayon and other man-made fabrics, sports goods, boat building, and match-boxes.

Forests play a significant role in preventing soil erosion. Explain how deforestation can lead to environmental degradation and affect the water cycle.

Answer

Deforestation Leads to Environmental Degradation:

1. Soil Erosion — Without tree roots to hold the soil, rainwater and wind erode the fertile topsoil.

2. Loss of Biodiversity — Forests are habitats for many species of animals, birds, insects and plants. Deforestation destroys these habitats.

3. Loss of Soil Fertility — Removal of forest cover exposes the soil to heat, wind and rain, reducing its fertility.

4. Increased Floods — With fewer trees to absorb rainwater, surface runoff increases, causing floods and silting of rivers and streams.

Effect on the Water Cycle:

1. Reduced Transpiration — Trees release water vapour into the atmosphere through transpiration. Deforestation reduces this process and may reduce rainfall.

2. Reduced Groundwater Recharge — Forests help rainwater seep into the ground. Deforestation causes rapid runoff, lowering the water table.

3. Drying of Rivers and Streams — Forests release water slowly into rivers throughout the year. Deforestation causes rivers to either flood during the rainy season or dry up during summer.

4. Loss of Soil Moisture — Without tree cover, soil loses moisture quickly due to direct sunlight and wind.