Let’s go through each question carefully and find the correct answers.
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I. Choose the correct answer.
1. Our atmosphere is divided into
5 layers.
→ The five layers are: Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.
✔ Answer: (a) 5
2.
Thermometer measures the temperature.
→ Barometer = air pressure, Rain Gauge = rainfall, Thermometer = temperature.
✔ Answer: (b) Thermometer
3. In
Thermosphere, temperature rises very rapidly with increasing height.
→ This layer gets super hot because it absorbs high-energy solar radiation.
✔ Answer: (a) Thermosphere
4. Green plants produce
Oxygen during photosynthesis.
→ They take in CO₂ and release O₂ using sunlight.
✔ Answer: (c) Oxygen
5. The uppermost layer of the atmosphere is known as
Exosphere.
→ It’s the outermost layer, fading into space.
✔ Answer: (b) Exosphere
6.
Oxygen is the second most plentiful gas in the air.
→ Nitrogen is #1 (~78%), Oxygen is #2 (~21%).
✔ Answer: (b) Oxygen
7. Almost all weather phenomena like rainfall, fog, and hailstorm occur in
Troposphere.
→ This is where we live and where clouds form.
✔ Answer: (b) Troposphere
8.
Thermosphere helps in radio transmission.
→ It reflects radio waves back to Earth, helping long-distance communication.
✔ Answer: (c) Thermosphere
9. Mesosphere, the third layer of the atmosphere, extends up to the height of
80 km.
→ From about 50 km to 80 km above Earth.
✔ Answer: (a) 80
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II. Fill in the blanks
1. Cold air is denser and
heavier. That is why it tends to sink down.
→ Warm air rises, cold air sinks — that’s how wind and weather start!
2.
Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere are the five layers of atmosphere.
→ Just list them from bottom to top.
3. On the Celsius scale, water freezes at
0°C and boils at
100°C.
→ Standard reference points for water.
4.
Plants need nitrogen for their survival.
→ Actually, many living things need nitrogen — but plants get it from soil (often via bacteria). Animals get it by eating plants or other animals. But since the blank says “need nitrogen”, and plants use it to grow, this fits.
*(Note: Some might say “Living organisms” — but given context, “Plants” is acceptable here.)*
5. Radio waves transmitted from the earth are reflected back to the earth by
Thermosphere.
→ Specifically, a part called the Ionosphere (within thermosphere) bounces radio signals.
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Final Answer:
I. Multiple Choice Answers:
1. (a) 5
2. (b) Thermometer
3. (a) Thermosphere
4. (c) Oxygen
5. (b) Exosphere
6. (b) Oxygen
7. (b) Troposphere
8. (c) Thermosphere
9. (a) 80
II. Fill in the Blanks:
1. heavier
2. Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere
3. 0°C, 100°C
4. Plants
5. Thermosphere
Parent Tip: Review the logic above to help your child master the concept of 7th grade geography worksheet.
