General Science Question Answers Chapter 16 Class 7 Maharashtra Board

Question Answers For All Chapters – General Science Class 7

Natural Resources

Exercise

1. Describe natural resources with reference to the following types:

(a) Mineral Resources

• Minerals are natural substances found in rocks and the earth’s crust.
• They are classified into metallic minerals (iron, copper, gold) and non-metallic minerals (mica, gypsum, diamond).
• Ores are minerals that contain a high proportion of metal.

(b) Forest Resources

• Forests provide wood, medicinal plants, fibers, rubber, paper, fruits, and honey.
• They help in preventing soil erosion, controlling floods, and maintaining ecological balance.
• Examples of trees used: Teak, Mahogany, Neem, Acacia.

(c) Ocean Resources

• Oceans contain minerals, natural gas, petroleum, salt, and marine life.
• Marine bio-resources include fish, prawns, shells, and seaweed.
• Mineral oil and natural gas are extracted from the seabed.

2. Answer the following questions:

(a) What is meant by fossil fuel? What are its types?

Fossil fuels are energy-rich substances formed from the remains of plants and animals buried underground for millions of years.

Types of Fossil Fuels:

1. Solid fuels: Coal, Peat, Lignite.
2. Liquid fuels: Petroleum, Diesel, Kerosene.
3. Gaseous fuels: Natural Gas, CNG, LPG.

(b) Make a list of the components we obtain from mineral oil.

• Petrol and Diesel – Used in vehicles.
• Kerosene – Used for cooking and lighting.
• Lubricating Oil – Used in machines.
• Tar – Used in road construction.
• Naphtha – Used in chemicals and plastics.

(c) What do we get from forests?

• Wood – Used for making furniture, houses, and tools.
• Medicinal plants – Used in Ayurvedic medicines.
• Paper and Rubber – Used for writing and making tires.
• Fruits and Honey – Used for food and health benefits.

(d) What are the items included in ocean resources? What are their uses?

✔ Mineral Resources:

• Petroleum and Natural Gas – Used as fuel.
• Salt – Used in food and medicines.
• Magnesium, Potassium, and Sulfur – Used in fertilizers and medicines.

✔ Biological Resources:

• Fish and seafood – Source of protein.
• Shells and Pearls – Used for ornaments and medicines.
• Seaweed – Used in cosmetics and food supplements.

(e) Why should we prevent the wastage of fuel used for vehicles?

• Fossil fuels like petrol and diesel are limited and take millions of years to form.
• Burning fuel releases pollutants like carbon dioxide, which causes global warming and air pollution.
• Saving fuel by using public transport, carpooling, and fuel-efficient vehicles helps in conserving resources and reducing pollution.

(f) Why is the diversity of plants and animals in the forests declining?

• Deforestation for agriculture, roads, and cities destroys natural habitats.
• Illegal hunting and poaching reduce wildlife populations.
• Pollution and climate change affect forests, leading to loss of biodiversity.
• Forest fires and overuse of resources also harm ecosystems.

(g) Write the names of five minerals and the useful substances obtained from them.

(h) Name the two important stages in the process of obtaining metals from ores.

✔ Extraction: The metal is removed from its ore through mining or other chemical processes.
✔ Purification: The extracted metal is refined to remove impurities and make it suitable for use.

3. What steps are taken for the protection and conservation of natural resources?

• Avoid deforestation – Plant more trees.
• Reduce fuel consumption – Use public transport and fuel-efficient vehicles.
• Control mining activities – Prevent over-extraction of minerals.
• Recycle and reuse materials – Reduce wastage of resources.
• Protect wildlife – Prevent hunting and habitat destruction.

4. Complete the flow chart:

Fuels → Fossil Fuels →

✔ Solid Fuels: Peat, Lignite, Bituminous Coal, Anthracite.
✔ Liquid Fuels: Mineral Oil.
✔ Gaseous Fuels: Natural Gas.

5. How does the economic condition of a nation depend on its natural resources?

• Rich mineral and fuel resources help in industrial growth.
• Forests provide wood and medicinal plants, boosting the economy.
• Oceans provide fish, petroleum, and transport routes, contributing to trade and commerce.

6. Which medicinal plants will you grow in your school and home? Why?

✔ Tulsi – Used for cough and cold.
✔ Neem – Has antibacterial properties.
✔ Aloe Vera – Used for skin problems.
✔ Ashwagandha – Used for immunity and stress relief.
✔ Amla – Rich in Vitamin C, boosts immunity.