Natural Resources MCQs Quiz | Class 9
This Class IX Science (Code 086) quiz covers the “Natural Resources” topic from the Additional Unit (Portfolio/Not Assessed in Year-End). Test your understanding of air, water, soil, and biogeochemical cycles as per the teacher’s note. Submit your answers to check your score and download the PDF for your portfolio.
Overview of Natural Resources
Natural resources are materials provided by nature that are essential for the survival of living organisms on Earth. The Earth constitutes four main domains: the Lithosphere (solid crust), the Hydrosphere (water bodies), the Atmosphere (blanket of air), and the Biosphere (zone where life exists). Understanding these resources is crucial for sustainable development.
Key Components
- Air (Atmosphere): A mixture of gases like Nitrogen (78%), Oxygen (21%), and others. It acts as a blanket, regulating Earth’s temperature and protecting life from harmful radiation.
- Water (Hydrosphere): Covers 75% of Earth’s surface. It is essential for all physiological activities in living organisms and acts as a universal solvent.
- Soil (Lithosphere): Formed by the weathering of rocks over millions of years. It provides nutrients for plant growth and is home to many organisms.
Biogeochemical Cycles
These cycles maintain the balance of nutrients in the biosphere through the movement of matter between biotic and abiotic components.
| Cycle Name | Key Process | Importance |
|---|---|---|
| Water Cycle | Evaporation, Condensation, Precipitation | Maintains water balance and regulates climate. |
| Nitrogen Cycle | Nitrogen Fixation, Nitrification | Essential for protein and DNA synthesis in organisms. |
| Carbon Cycle | Photosynthesis, Respiration, Combustion | Regulates global temperature and energy flow. |
Quick Revision Notes
- The Greenhouse Effect: Increase in global temperature due to gases like Carbon Dioxide and Methane trapping heat.
- Ozone Layer: A layer in the stratosphere containing O3 molecules that shields Earth from harmful UV radiation.
- Pollution: Contamination of air, water, or soil by harmful substances (pollutants) affecting life quality.
- Soil Erosion: Removal of the topsoil by wind or water, often caused by deforestation.
Extra Practice Questions
- What is the major source of fresh water in the city?
- Name two biologically important compounds that contain both Nitrogen and Oxygen.
- How do forests help in the conservation of soil?
- What is the difference between smog and fog?
- Why is the atmosphere essential for life?
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