Nature's Treasures — Hard

Q1. Consider the following statements about the composition of air shown in Fig. 11.1: I. Nitrogen occupies 78 of the 100 squares. II. Oxygen occupies 21 of the 100 squares. III. Argon, carbon dioxide and other gases together occupy 10 of the 100 squares. Which of the statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q2. Which of the following uses of a windmill are mentioned in the chapter? I. Running a flour mill II. Pulling up water from a well III. Generating electricity Select the correct combination.

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q3. Consider the following statements about freshwater on Earth: I. Freshwater is present in ice sheets or snow. II. Freshwater is found in rivers and lakes on the surface. III. All saline water in oceans is freshwater for domestic use. Which of the statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q4. Assertion (A): Stepwells like Bawadi in Rajasthan and Vav in Gujarat were built in these regions and not in coastal Kerala. Reason (R): These two states face severe scarcity of water and stepwells help store rainwater and seeping water for later use. Choose the correct option.

• A. Both A and R are true, and R is the correct explanation of A.
• B. Both A and R are true, but R is NOT the correct explanation of A.
• C. A is true, R is false.
• D. A is false, R is true.

Q5. A family uses solar panels to generate electricity, a gas stove to cook food and a windmill to pump water. If there is no sunlight for a week, which appliances will be affected?

• A. Only the gas stove
• B. Only the windmill
• C. Both the solar panels and (indirectly) the windmill — sunlight drives wind too; the gas stove still works
• D. All three stop working immediately

Q6. Consider the following statements about forests: I. Forest cover has been decreasing mainly due to large-scale cutting of trees. II. It takes many years to grow a new forest or restore lost forests. III. New forests can be regrown overnight after rain. Which are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q7. Assertion (A): Rocks should be conserved and used responsibly. Reason (R): It takes thousands to millions of years to form rocks. Choose the correct option.

• A. Both A and R are true, and R is the correct explanation of A.
• B. Both A and R are true, but R is NOT the correct explanation of A.
• C. A is true, R is false.
• D. A is false, R is true.

Q8. The chapter mentions that a basic mobile phone contains about a dozen minerals. Which set lists minerals named for this example?

• A. Gold, silver, copper, cobalt
• B. Petroleum, coal, natural gas, LPG
• C. Slate, laterite, granite, marble
• D. Tulsi, neem, mango, rose

Q9. Consider the following statements about fossil fuels: I. They are formed from the remains of microorganisms and plants buried deep inside the earth. II. It takes millions of years for these fuels to form. III. They are found in unlimited quantities on Earth. Which of the statements are correct?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q10. When fossil fuels are burnt, which of the following are produced and pollute the air? I. Smoke II. Carbon dioxide gas III. Oxygen Select the correct combination.

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q11. Why is petroleum classified as a non-renewable resource?

• A. Because it is found only in Asia
• B. Because it takes millions of years to form and gets exhausted once used
• C. Because it is renewed every year by the Sun
• D. Because it is a human-made resource

Q12. Classify the following as renewable (R) or non-renewable (NR): (i) Coal (ii) Natural gas (iii) Forests (iv) Minerals Which option gives the correct classification?

• A. (i) R, (ii) R, (iii) NR, (iv) NR
• B. (i) NR, (ii) NR, (iii) R, (iv) NR
• C. (i) NR, (ii) R, (iii) R, (iv) R
• D. (i) R, (ii) NR, (iii) R, (iv) R

Q13. Bhoomi and Surya notice that the air in their city does not smell as good as the air at Ajji's village. Amma explains the difference. The most likely reason as given in the chapter is

• A. The city is at a higher altitude
• B. The city has very few trees and many vehicles using fossil fuels, producing smoke
• C. The city has too much rain in summer
• D. The village uses petrol while the city uses CNG

Q14. Cutting down trees on a large scale impacts the quality of soil. The best explanation, based on the chapter, is

• A. Trees release acid into the soil while alive
• B. Without trees, roots no longer hold the soil and fallen leaves no longer decay into nutrients, so the soil washes away and loses nutrients
• C. Trees increase salt content in the soil
• D. Trees use up all the water in the soil, leaving it dry

Q15. Which of the following lists contains ONLY natural resources?

• A. Air, water, electric bulb, soil
• B. Forests, sunlight, minerals, fossil fuels
• C. Furniture, bicycle, solar panel, bricks
• D. Water, food, machines, plastic