Class 5 Science Chapter 13 HOTS Questions - Our Environment

Q1: Which of the following best describes a biodegradable material?
(a) Materials that can be easily recycled
(b) Materials that can decompose naturally by living organisms
(c) Materials that are harmful to the environment
(d) Materials that are made from renewable resources
Ans: (b)
Biodegradable materials can be broken down naturally by living organisms, reducing environmental pollution.

Q2: What is the main source of energy for the water cycle?
(a) Sun
(b) Wind
(c) Moon
(d) Earth's core
Ans: (a)
The Sun provides the energy needed to drive the water cycle by causing evaporation, leading to condensation and precipitation.

Q3: Which of the following is an example of a primary consumer in a food chain?
(a) Lion
(b) Deer
(c) Grass
(d) Snake
Ans: (b)
Primary consumers, like deer, feed directly on plants (producers) in a food chain.

Q4: What is the role of decomposers in an ecosystem?
(a) They consume other organisms for food.
(b) They convert sunlight into energy through photosynthesis.
(c) They break down dead organic matter into simple substances.
(d) They help in pollination of flowers.
Ans: (c)
Decomposers break down dead plants and animals into simpler substances, recycling nutrients back into the ecosystem.

Q5: Which gas is most abundant in the Earth's atmosphere?
(a) Carbon dioxide
(b) Nitrogen
(c) Oxygen
(d) Hydrogen
Ans: (b)
Nitrogen makes up approximately 78% of the Earth's atmosphere, making it the most abundant gas.

Q6: Which environmental issue is primarily caused by the burning of fossil fuels?
(a) Global warming
(b) Soil erosion
(c) Deforestation
(d) Acid rain
Ans: (a)
Burning fossil fuels releases greenhouse gases like carbon dioxide, leading to global warming and climate change.

Q7: Which human activity is most likely to reduce air pollution?
(a) Increasing the use of plastic products
(b) Using public transportation instead of private cars
(c) Disposing of waste in open areas
(d) Burning leaves in the backyard
Ans: (b)
Using public transportation reduces the number of vehicles on the road, leading to lower air pollution levels.

Q8: Which of the following is a renewable source of energy?
(a) Coal
(b) Natural gas
(c) Solar power
(d) Petroleum
Ans: (c)
Solar power is a renewable energy source as it is derived from sunlight, which is constantly available.

Q9: Which layer of the Earth's atmosphere is responsible for reflecting radio waves, enabling long-distance communication?
(a) Troposphere
(b) Stratosphere
(c) Ionosphere
(d) Exosphere
Ans: (c)
The ionosphere is responsible for reflecting radio waves, allowing long-range communication.

Q10: How does deforestation affect the environment?
(a) It helps in maintaining ecological balance.
(b) It leads to an increase in wildlife diversity.
(c) It causes soil erosion and disrupts the water cycle.
(d) It reduces the concentration of carbon dioxide in the atmosphere.
Ans: (c)
Deforestation disrupts the natural balance, leading to soil erosion, loss of biodiversity, and disturbance in the water cycle.