CBSE Class 6 Science Chapter 11: Nature's Treasures — Assertion & Reason
CBSE Class 6 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 11: Nature's Treasures from the NCERT Class 6 Science textbook Curiosity. Each question has four options — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(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, but R is false.
(d) A is false, but R is true.
(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, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): Humans can survive without oxygen for only a few minutes.
Reason (R): Our body continuously needs oxygen from the air to perform its vital functions.
Reason (R): Our body continuously needs oxygen from the air to perform its vital functions.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The constant supply of oxygen is an absolute requirement for human survival and bodily functions.
2
Assertion (A): Oxygen is the most abundant gas in the Earth's atmosphere.
Reason (R): Air is a mixture of gases, out of which nitrogen occupies about 78 percent.
Reason (R): Air is a mixture of gases, out of which nitrogen occupies about 78 percent.
Answer: (d)
A is false, but R is true. Nitrogen is the most abundant gas in the atmosphere at 78%, while oxygen only occupies about 21%.
3
Assertion (A): A paper firki rotates when it is held outdoors on a breezy day.
Reason (R): Moving air, called wind, exerts a force that turns the blades of the firki.
Reason (R): Moving air, called wind, exerts a force that turns the blades of the firki.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The kinetic energy of the wind pushes the blades, causing the firki to spin.
4
Assertion (A): Windmills can be used to pull up underground water and generate electricity.
Reason (R): Windmills utilise the energy of the wind to rotate their wings and perform mechanical work.
Reason (R): Windmills utilise the energy of the wind to rotate their wings and perform mechanical work.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The rotating wings of a windmill harness the wind's energy to drive pumps or electric generators.
5
Assertion (A): The water found in oceans and seas is highly suitable for domestic and agricultural use.
Reason (R): Water covers about two-thirds of the Earth's surface.
Reason (R): Water covers about two-thirds of the Earth's surface.
Answer: (d)
A is false, but R is true. While oceans cover a vast area, their water is saline (salty) and is not fit for direct domestic or agricultural use without desalination.
6
Assertion (A): Stepwells like Bawadi in Rajasthan are excellent structures for water harvesting.
Reason (R): Stepwells only store direct rainwater and strictly prevent groundwater seepage.
Reason (R): Stepwells only store direct rainwater and strictly prevent groundwater seepage.
Answer: (c)
A is true, but R is false. Stepwells are great for water harvesting, but they are specifically designed to allow seepage of groundwater from nearby lakes and rivers through their stone walls, in addition to catching rainwater.
7
Assertion (A): The Sun is considered the main source of energy for life on Earth.
Reason (R): Plants use energy from the Sun to produce food, which in turn sustains animals and humans.
Reason (R): Plants use energy from the Sun to produce food, which in turn sustains animals and humans.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Because the entire food web relies on plants performing photosynthesis using sunlight, the Sun is the ultimate energy source for living beings.
8
Assertion (A): Solar panels are devices that capture the Sun's energy to produce electricity.
Reason (R): Solar energy is considered a non-renewable natural resource.
Reason (R): Solar energy is considered a non-renewable natural resource.
Answer: (c)
A is true, but R is false. Solar panels do generate electricity from sunlight, but solar energy is a renewable resource because it is continuously replenished by nature.
9
Assertion (A): The roots of plants in a forest help in preventing soil erosion.
Reason (R): The leaves that fall from the trees decay and enrich the soil with nutrients.
Reason (R): The leaves that fall from the trees decay and enrich the soil with nutrients.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. While both statements are true benefits of a forest ecosystem, fallen leaves providing nutrients does not explain how roots physically hold the soil together to prevent erosion.
10
Assertion (A): The Chipko movement in the early 1970s successfully protected many forest areas from being felled.
Reason (R): Local women actively participated by encircling and physically hugging the trees to stop loggers.
Reason (R): Local women actively participated by encircling and physically hugging the trees to stop loggers.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The physical act of hugging the trees (Chipko) was the direct mechanism the community used to prevent deforestation.
11
Assertion (A): Soil is formed very quickly within a few months by the action of wind and water.
Reason (R): Soil formation occurs through the continuous disintegration of rocks over thousands of years.
Reason (R): Soil formation occurs through the continuous disintegration of rocks over thousands of years.
Answer: (d)
A is false, but R is true. Soil formation is an incredibly slow natural process that takes thousands to millions of years, not just a few months.
12
Assertion (A): Laterite rocks can be cut and used as bricks for constructing buildings.
Reason (R): Rocks and minerals play a vital role in human lives and infrastructure.
Reason (R): Rocks and minerals play a vital role in human lives and infrastructure.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. The general importance of rocks does not scientifically explain the specific structural properties that make laterite suitable for bricks.
13
Assertion (A): Metals like gold, copper, iron, and aluminium are extracted from minerals.
Reason (R): Minerals are naturally occurring substances found inside rocks.
Reason (R): Minerals are naturally occurring substances found inside rocks.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. R simply defines what a mineral is; it doesn't explain the metallurgical extraction process of metals from those minerals.
14
Assertion (A): Petrol, diesel, and kerosene are obtained from a natural resource called petroleum.
Reason (R): Petroleum is a human-made resource produced rapidly in chemical laboratories.
Reason (R): Petroleum is a human-made resource produced rapidly in chemical laboratories.
Answer: (c)
A is true, but R is false. Petroleum is a natural fossil fuel that takes millions of years to form deep inside the earth; it is not human-made.
15
Assertion (A): Coal, petroleum, and natural gas are called fossil fuels.
Reason (R): They are formed from the remains of microorganisms and plants that got buried deep inside the earth millions of years ago.
Reason (R): They are formed from the remains of microorganisms and plants that got buried deep inside the earth millions of years ago.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The term "fossil" directly refers to the ancient, buried remains of living organisms from which these fuels are generated.
16
Assertion (A): Compressed Natural Gas (CNG) is increasingly being used as a fuel for vehicles instead of petrol or diesel.
Reason (R): CNG is a cleaner fuel and causes significantly less air pollution.
Reason (R): CNG is a cleaner fuel and causes significantly less air pollution.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The shift towards CNG in public transport is primarily driven by its environmental benefit of producing less smoke and harmful emissions.
17
Assertion (A): Air, water, and forests are examples of non-renewable natural resources.
Reason (R): Non-renewable resources are found in limited quantities and take millions of years to form.
Reason (R): Non-renewable resources are found in limited quantities and take millions of years to form.
Answer: (d)
A is false, but R is true. Air, water, and forests are renewable resources because they get replenished by natural processes within a reasonable period. The definition of non-renewable resources in R is correct.
18
Assertion (A): Forests are considered renewable resources.
Reason (R): If preserved and used responsibly, forests can naturally regrow and replenish themselves over time.
Reason (R): If preserved and used responsibly, forests can naturally regrow and replenish themselves over time.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The ability of forests to regenerate and restore their lost cover is exactly what classifies them as a renewable resource.
19
Assertion (A): Solar panels, bicycles, and furniture are classified as natural resources.
Reason (R): All resources created by human beings for their convenience are called human-made resources.
Reason (R): All resources created by human beings for their convenience are called human-made resources.
Answer: (d)
A is false, but R is true. Solar panels, bicycles, and furniture are human-made resources, not natural resources, because they are manufactured by humans.
20
Assertion (A): We should reduce our over-dependence on fossil fuels and use them judiciously.
Reason (R): Fossil fuels are non-renewable and burning them produces harmful smoke and carbon dioxide that pollute the air.
Reason (R): Fossil fuels are non-renewable and burning them produces harmful smoke and carbon dioxide that pollute the air.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The limited supply of fossil fuels combined with their negative environmental impact are the primary reasons we need to conserve them and find alternatives.
❓ Frequently Asked Questions
What is covered in CBSE Class 6 Science Chapter 11 Nature\'s Treasures?
This chapter covers all key topics from Nature\'s Treasures as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 6 board exam preparation covering the complete syllabus.
Are these CBSE Class 6 Science Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 6 Science?
All chapters of CBSE Class 6 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study Nature\'s Treasures online for free?
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