Very Short Answer Questions - 1 Mark

Q1. What are renewable resources?

Ans. Resources which can replenish themselves by quick recycling are called renewable resources. For example, forests and wildlife.

Q2. What are the two main causes of over-exploitation of natural resources?

Ans. Growing population and industrialisation.

Q3. Name the component of air that has maximum solubility in water.

Ans. Carbon dioxide

Q4. In which zone of atmosphere is ozone layer present?

Ans. Stratosphere

Q5. Which gas is added to the atmosphere by the decay of organic matter?

Ans. Carbon dioxide

Q6. Name the two things essential for existence of life on Earth.

Ans. (i) Natural resources like air, land and water.
        (ii) Energy of the Sun.

Q7. Name the processes which help to maintain the balance between oxygen and carbon dioxide in the environment.

Ans. Photosynthesis and respiration.

Q8. What are the two forms of elemental oxygen found in the atmosphere?

Ans. Molecular oxygen and ozone.

Q9. Which group of organisms is poisoned by elemental oxygen?

Ans. Anaerobic bacteria

Q10. What is the effect of oxygen on nitrogen fixation?

Ans. Nitrogen fixation cannot take place in the presence of oxygen.

Q11. What are the basic requirements for existence of life?

Ans. Food, water, air and optimum temperature.

Q12. How is humus a major factor in deciding the soil structure?

Ans. Humus makes the soil more porous and allows the water and air to penetrate deep in soil.

Q13. What are clouds?

Ans. Clouds are collection of tiny particles of liquid or solid water occurring in the atmosphere above the Earth's surface.

Q14. Name any one source of freshwater.

Ans. Rainwater

Q15. From where do we procure table salt?

Ans. From sea water

Q16. Give any two uses of groundwater.

Ans. It is used for human consumption and irrigation. purposes

Q17. Why step farming is common in hills?

Ans. Step farming is practised in hills to check soil erosion through water currents on the slopes.

Q18. What is topsoil?

Ans. The topmost layer of the soil which contains soil particles, humus, as well as living organisms is called topsoil.

Q19. What do you mean by fertility of the soil?

Ans. Fertility is the capacity of the soil to sustain plant life with the required nutrients.

Q20. What are biodegradable pollutants?

Ans. They are the pollutants that degrade by natural means. For example, paper, excreta of animals, etc.

Q21. Name the organisms that help in bringing back the minerals from the living system to the nutrient pool.

Ans. Decomposers

Q22. Which group of plants has nitrogen-fixing bacteria in the root nodules?

Ans. Leguminous plants

Q23. Name the organism found in the root nodules of leguminous plants.

Ans.  bacteria.

Q24. What are CFCs?

Ans. CFCs or chlorofluorocarbons are man-made organo-halogens used in refrigerators that degrade the ozone layer.

Q25. The atmosphere of the Earth is heated by which radiations?

Ans. Through long wave radiations re-radiated by land and water.

Q26. How are the nitrogen molecules present in air converted into nitrates and nitrites?

Ans. By the biological process of nitrogen fixing bacteria present in soil.

Q27. What is 'ozone hole'?

Ans. The thinning of ozone layer at few places is called the ozone hole.

Q28. What is the major source of mineral in soil?

Ans. The parent rock from which soil is formed.

Q29. What does marked temperature changes in aquatic environment mainly affect?

Ans. Breeding of aquatic animals.