Nature’s Treasures

Given: A figure (Fig. 11.9) showing various natural resources with jumbled names.

Note: Since the actual figure and jumbled names cannot be seen from the OCR, the common natural resources shown in such exercises are listed below with their classification.

| S. No. | Name of Resource | Renewable / Non-Renewable |
|--------|-----------------|---------------------------|
| 1 | Air | Renewable |
| 2 | Water | Renewable |
| 3 | Sunlight (Solar energy) | Renewable |
| 4 | Forests (Trees) | Renewable |
| 5 | Soil | Renewable (very slowly) |
| 6 | Coal | Non-Renewable |
| 7 | Petroleum | Non-Renewable |
| 8 | Natural Gas | Non-Renewable |
| 9 | Minerals/Rocks | Non-Renewable |

Concept used: Resources that are replenished by natural processes within a reasonable time are renewable. Resources present in limited quantities that cannot be replenished within a reasonable time are non-renewable.

Concept used: Natural resources are those provided by nature; human-made resources are created by humans. Renewable resources are replenished naturally; non-renewable resources are not.

(i) Nature has all the resources to meet human needs.
Answer: True [T]
Nature provides all essential resources such as air, water, sunlight, soil, forests, minerals and fossil fuels that are needed to meet human needs.

(ii) Machines are a resource found in nature.
Answer: False [F]
Correction: Machines are human-made resources, not found in nature. They are created by humans using natural resources.

(iii) Natural gas is a non-renewable resource.
Answer: True [T]
Natural gas is a fossil fuel formed over millions of years and cannot be replenished within a reasonable period, so it is a non-renewable resource.

(iv) Air is a renewable resource.
Answer: True [T]
Air is continuously replenished by natural processes (e.g., photosynthesis restores oxygen), so it is a renewable resource.

(i) Answer: (b) Petrol
Justification: Petrol is the most commonly used fuel in two-wheelers such as scooters and bikes because it is suitable for small, high-speed engines. Kerosene is used in lamps/stoves, diesel in heavy vehicles, and LPG in cooking.

(ii) Answer: (b) Water
Justification: Water is a renewable resource because it is continuously replenished through the water cycle (evaporation, condensation and precipitation). Coal, natural gas and petrol are fossil fuels and are non-renewable resources.

Given resources: Coal, Natural gas, Forests, Minerals

Concept used: Renewable resources are replenished by natural processes within a reasonable time. Non-renewable resources exist in limited quantities and take millions of years to form.

| Resource | Classification | Reason |
|----------|---------------|--------|
| Coal | Non-Renewable | Formed from remains of organisms over millions of years; cannot be replenished quickly. |
| Natural Gas | Non-Renewable | A fossil fuel formed over millions of years; present in limited quantities. |
| Forests | Renewable | Trees can be regrown through natural processes and human efforts (afforestation). |
| Minerals | Non-Renewable | Found in limited quantities in the Earth's crust; take millions of years to form. |

Conclusion:
- Renewable: Forests
- Non-Renewable: Coal, Natural Gas, Minerals

Given: Petroleum as a resource.

Concept used: Non-renewable resources are those that exist in limited quantities and cannot be replenished within a reasonable period of time.

Answer:
We say that petroleum is a non-renewable resource because:
1. Formation time: Petroleum is formed from the remains of microorganisms and plants that got buried deep inside the Earth millions of years ago. It takes millions of years to form.
2. Limited quantity: The reserves of petroleum present in the Earth are limited and are being used up rapidly.
3. Cannot be replenished: Once used, petroleum cannot be replenished within a human lifetime or even within thousands of years.

Since we are consuming petroleum much faster than it can be formed, it will eventually run out. Therefore, petroleum is called a non-renewable resource.

Given: Statement — It is difficult to regrow forests.

Justification:

Although forests are classified as renewable resources, it is very difficult to regrow them because of the following reasons:

1. Time required: A forest is not just a collection of trees — it is a complex ecosystem. It takes hundreds of years for a forest to develop fully with all its layers of vegetation, diverse species of plants, animals, insects and microorganisms.

2. Interdependence of species: Forests have a large number of interdependent species. When a forest is cut down, many species lose their habitat and may become extinct. Restoring this biodiversity is extremely difficult.

3. Soil degradation: When trees are cut, the roots no longer hold the soil. The topsoil gets washed away by rain (soil erosion), making the land less fertile and unsuitable for new plant growth.

4. Loss of nutrients: Fallen leaves from trees decay and enrich the soil. Without trees, this natural recycling of nutrients stops, making it harder for new plants to grow.

5. Climate changes: Deforestation changes the local climate — it reduces rainfall and increases temperature — making it harder for new trees to survive.

Conclusion: Due to these reasons, even though forests are technically renewable, regrowing them to their original state is extremely difficult and time-consuming.

Given: Daily activities involving natural resources.

Concept used: Natural resources include air, water, soil, forests, fossil fuels, minerals, etc. Responsible use helps conserve them for the future.

| S. No. | Daily Activity | Natural Resource Used | Ways to Reduce Use |
|--------|---------------|----------------------|--------------------|
| 1 | Drinking and washing | Water | Turn off taps when not in use; fix leaking taps; reuse water where possible. |
| 2 | Cooking food | LPG / Natural gas, Water | Use pressure cookers to save fuel; cook the right quantity to avoid wastage. |
| 3 | Travelling to school | Petrol / Diesel | Use public transport, carpool, cycle or walk for short distances. |
| 4 | Using paper (notebooks, books) | Forests (wood/trees) | Write on both sides of paper; reuse old notebooks; recycle paper. |
| 5 | Using electricity (fans, lights, TV) | Coal / Water (used in power plants) | Switch off lights and fans when not in use; use energy-efficient LED bulbs. |

Conclusion: By making small changes in our daily habits, we can significantly reduce the consumption of natural resources and help conserve them for future generations.

Given: The role of air in enabling various activities.

Concept used: Air contains oxygen (needed for breathing and burning), and wind (moving air) can be used for various purposes.

Four activities possible due to the presence of air:

1. Breathing: All living beings — humans, animals and plants — breathe in oxygen from the air to survive and carry out their body functions.

2. Flying kites and running windmills: Moving air (wind) helps kites fly and rotates the blades of windmills, which can be used to generate electricity or pump water.

3. Burning of fuels: Air (oxygen in air) supports combustion. Cooking on a gas stove, burning wood, and running vehicle engines are all possible because of oxygen in the air.

4. Pollination and seed dispersal: Wind (moving air) helps in the pollination of flowers and dispersal of seeds of many plants, which is essential for plant reproduction and growth of forests.