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ICSE Class 7 Geography Question 14 of 16

Atmosphere — Question 14

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Question

Question 4(xii)

Which gas is released from the use of chemical fertilizers and pesticides? In what way does it affect the atmosphere?

Answer

Nitrous oxide is released from the use of chemical fertilizers and pesticides.
Nitrous oxide is a greenhouse gas that causes greenhouse effect and contributes to global warming.

Source: This question is from Atmosphere, Geography — Class 7, ICSE Board.

Key Concepts Covered

This question tests your understanding of the following concepts from the chapter Atmosphere: Question, Xii, Gas, Released, Use, Chemical. These are fundamental topics in Geography that students are expected to master as part of the ICSE Class 7 curriculum.

A thorough understanding of these concepts will help you answer similar questions confidently in your ICSE examinations. These topics are frequently tested in both objective and subjective sections of Geography papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.

How to Approach This Question

Read the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.

Key Points to Remember

  • Reference specific locations, latitudes, or regions in your answers.
  • Explain both physical and human factors where applicable.
  • Use map references and diagrams to strengthen answers.
  • Link geographic concepts to current real-world examples.

Related Questions from Atmosphere

Practice more questions from Atmosphere — Geography, Class 7 ICSE

ICSE Class VII Geography — Chapter 3: Atmosphere

Bright Tutorials | ICSE Class VII | Geography | Chapter 3

Composition of the Atmosphere

The atmosphere is the blanket of air surrounding the earth, held by gravity. It is composed primarily of nitrogen (78%) and oxygen (21%), with argon (0.93%), carbon dioxide (0.04%), and traces of water vapour and other gases. Nitrogen dilutes oxygen and supports plant growth, oxygen is essential for breathing, and carbon dioxide helps trap heat through the greenhouse effect.

Five Layers of the Atmosphere

The atmosphere has five layers: the Troposphere (0-12 km, where all weather occurs), Stratosphere (12-50 km, contains the ozone layer), Mesosphere (50-80 km, coldest layer where meteors burn), Thermosphere (80-700 km, auroras and ISS orbit here), and Exosphere (700+ km, merges with space). Temperature decreases in the troposphere and mesosphere but increases in the stratosphere and thermosphere.

Atmospheric Pressure and Pressure Belts

Atmospheric pressure is the weight of air pressing down on the earth's surface, measured by a barometer. Normal pressure at sea level is 1,013.25 mb. Pressure decreases with altitude. The earth has four major pressure belts: Equatorial Low (0°), Subtropical High (30°), Subpolar Low (60°), and Polar High (90°). Wind flows from high pressure to low pressure areas.

Types of Winds

Planetary winds blow constantly: Trade Winds (towards equator), Westerlies (towards poles from 30°), and Polar Easterlies (from poles). Periodic winds change direction: monsoons change seasonally, while land and sea breezes change daily. Sea breeze blows during the day (land heats faster), land breeze at night (land cools faster). Local winds like the Loo (India), Chinook (Rockies), and Mistral (France) are caused by local conditions.

Key Takeaways for ICSE Class VII Students

  • Memorise: Nitrogen 78%, Oxygen 21% — these two make up 99% of the atmosphere
  • Use the mnemonic "The Sun Makes Things Exciting" for layer order
  • Wind always blows from HIGH pressure to LOW pressure
  • Sea breeze = daytime, Land breeze = nighttime
  • Draw and label the atmosphere layers diagram for exam preparation