1. What is meant by Earth as a system?
A. Earth consists only of land
B. Earth consists of interacting components that work together
C. Earth is made only of living organisms
D. Earth receives no energy from outside
Answer: B. Earth consists of interacting components that work together
2. Which of the following is an important source of energy for most processes on Earth?
A. Moon
B. Sun
C. Oceans
D. Soil
Answer: B. Sun
3. The four major spheres of Earth are:
A. Atmosphere, hydrosphere, geosphere and biosphere
B. Lithosphere, Sun, Moon and atmosphere
C. Oceans, rivers, mountains and forests
D. Soil, rocks, plants and animals
Answer: A. Atmosphere, hydrosphere, geosphere and biosphere
4. The layer of gases surrounding Earth is called the:
A. Biosphere
B. Hydrosphere
C. Atmosphere
D. Geosphere
Answer: C. Atmosphere
5. All water present on, below and above Earth’s surface is collectively called the:
A. Atmosphere
B. Hydrosphere
C. Geosphere
D. Biosphere
Answer: B. Hydrosphere
6. The solid part of Earth, including rocks, minerals and soil, is mainly associated with the:
A. Biosphere
B. Atmosphere
C. Geosphere
D. Hydrosphere
Answer: C. Geosphere
7. The part of Earth where living organisms exist is called the:
A. Atmosphere
B. Biosphere
C. Geosphere
D. Hydrosphere
Answer: B. Biosphere
8. Which statement about Earth’s spheres is correct?
A. They function independently of one another
B. They continuously interact with one another
C. Only the atmosphere interacts with the biosphere
D. Only the hydrosphere changes with time
Answer: B. They continuously interact with one another
9. Which process converts solar energy into chemical energy stored in food?
A. Respiration
B. Photosynthesis
C. Decomposition
D. Evaporation
Answer: B. Photosynthesis
10. During photosynthesis, green plants primarily use:
A. Oxygen and glucose
B. Carbon dioxide and water
C. Nitrogen and oxygen
D. Methane and water
Answer: B. Carbon dioxide and water
11. Which pigment enables green plants to absorb light energy for photosynthesis?
A. Haemoglobin
B. Chlorophyll
C. Melanin
D. Keratin
Answer: B. Chlorophyll
12. The ultimate source of energy for most ecosystems is:
A. Soil
B. Water
C. Sunlight
D. Wind
Answer: C. Sunlight
13. Energy generally flows through an ecosystem:
A. In a circular manner
B. From producers to consumers and eventually to decomposers
C. From consumers to the Sun
D. From decomposers to producers only
Answer: B. From producers to consumers and eventually to decomposers
14. Organisms that make their own food are called:
A. Consumers
B. Decomposers
C. Producers
D. Parasites
Answer: C. Producers
15. Which of the following is a producer?
A. Grass
B. Lion
C. Mushroom
D. Earthworm
Answer: A. Grass
16. Animals that obtain food by eating plants are called:
A. Primary consumers
B. Producers
C. Decomposers
D. Secondary producers
Answer: A. Primary consumers
17. Which organism is most likely to be a primary consumer?
A. Tiger
B. Grasshopper
C. Eagle
D. Mushroom
Answer: B. Grasshopper
18. Organisms that break down dead organic matter are called:
A. Producers
B. Herbivores
C. Decomposers
D. Predators
Answer: C. Decomposers
19. Which of the following is an example of a decomposer?
A. Grass
B. Mushroom
C. Deer
D. Tiger
Answer: B. Mushroom
20. A food chain represents:
A. The movement of energy and matter through feeding relationships
B. Only the movement of water
C. Only the movement of oxygen
D. The movement of rocks between Earth and space
Answer: A. The movement of energy and matter through feeding relationships
21. Which sequence represents a simple food chain?
A. Grass → Deer → Tiger
B. Tiger → Deer → Grass
C. Deer → Grass → Tiger
D. Grass → Tiger → Deer
Answer: A. Grass → Deer → Tiger
22. The water cycle describes the continuous movement of water between:
A. Only oceans and rivers
B. Atmosphere, land and water bodies
C. Only plants and animals
D. Rocks and minerals only
Answer: B. Atmosphere, land and water bodies
23. The conversion of liquid water into water vapour is called:
A. Condensation
B. Evaporation
C. Precipitation
D. Infiltration
Answer: B. Evaporation
24. The process by which water vapour changes into liquid water is:
A. Evaporation
B. Condensation
C. Transpiration
D. Runoff
Answer: B. Condensation
25. Rain, snow and hail are forms of:
A. Evaporation
B. Condensation
C. Precipitation
D. Transpiration
Answer: C. Precipitation
26. Water released into the atmosphere from plant leaves is mainly through:
A. Respiration
B. Transpiration
C. Condensation
D. Infiltration
Answer: B. Transpiration
27. Water flowing over the land surface into rivers, lakes and oceans is called:
A. Runoff
B. Condensation
C. Transpiration
D. Sublimation
Answer: A. Runoff
28. The movement of water into the soil is called:
A. Evaporation
B. Infiltration
C. Condensation
D. Precipitation
Answer: B. Infiltration
29. The carbon cycle involves the movement of carbon between:
A. Only plants and animals
B. Living organisms, atmosphere, oceans and Earth’s materials
C. Only the atmosphere and oceans
D. Only soil and plants
Answer: B. Living organisms, atmosphere, oceans and Earth’s materials
30. Which process removes carbon dioxide from the atmosphere?
A. Photosynthesis
B. Respiration
C. Combustion
D. Decomposition
Answer: A. Photosynthesis
31. Which process releases carbon dioxide into the atmosphere?
A. Photosynthesis
B. Respiration
C. Carbon fixation
D. Plant growth
Answer: B. Respiration
32. Burning of fossil fuels mainly releases:
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen
Answer: B. Carbon dioxide
33. Coal, petroleum and natural gas are examples of:
A. Renewable resources
B. Fossil fuels
C. Minerals only
D. Biomass producers
Answer: B. Fossil fuels
34. Which gas is an important greenhouse gas?
A. Carbon dioxide
B. Helium
C. Neon
D. Argon
Answer: A. Carbon dioxide
35. The greenhouse effect occurs because certain gases:
A. Block all sunlight from reaching Earth
B. Absorb and re-emit some outgoing infrared radiation
C. Remove all oxygen from the atmosphere
D. Prevent evaporation completely
Answer: B. Absorb and re-emit some outgoing infrared radiation
36. Which of the following is a greenhouse gas?
A. Carbon dioxide
B. Oxygen only
C. Nitrogen only
D. Hydrogen only
Answer: A. Carbon dioxide
37. An increase in the concentration of greenhouse gases can contribute to:
A. Global warming
B. Decreased solar energy
C. Complete disappearance of clouds
D. Stopping the water cycle
Answer: A. Global warming
38. Which activity can increase the amount of carbon dioxide in the atmosphere?
A. Planting trees
B. Burning fossil fuels
C. Photosynthesis
D. Forest conservation
Answer: B. Burning fossil fuels
39. The nitrogen cycle is important because nitrogen is required for the formation of:
A. Proteins and nucleic acids
B. Only water
C. Oxygen gas
D. Carbon dioxide
Answer: A. Proteins and nucleic acids
40. Atmospheric nitrogen cannot generally be used directly by most plants because:
A. Nitrogen is too heavy
B. It must first be converted into usable nitrogen compounds
C. Plants do not require nitrogen
D. Nitrogen is absent from the atmosphere
Answer: B. It must first be converted into usable nitrogen compounds
41. Which organisms play an important role in converting atmospheric nitrogen into usable forms?
A. Certain bacteria
B. All animals
C. Viruses only
D. Fungi only
Answer: A. Certain bacteria
42. Matter in Earth’s systems:
A. Is continuously created from nothing
B. Is continuously destroyed
C. Cycles through different parts of the Earth system
D. Exists only in living organisms
Answer: C. Cycles through different parts of the Earth system
43. Energy and matter behave differently in an ecosystem because:
A. Energy generally flows through the system, while matter can be recycled
B. Both energy and matter disappear after use
C. Matter flows only from the Sun
D. Energy is continuously recycled in exactly the same way as matter
Answer: A. Energy generally flows through the system, while matter can be recycled
44. Which of the following best demonstrates an interaction between the biosphere and hydrosphere?
A. Plants absorbing water from the soil
B. Rocks breaking down due to temperature changes
C. Clouds reflecting sunlight
D. Earth orbiting the Sun
Answer: A. Plants absorbing water from the soil
45. Which example shows interaction between the atmosphere and biosphere?
A. Plants taking in carbon dioxide for photosynthesis
B. Rocks melting underground
C. Water flowing through a river
D. Minerals crystallising inside rocks
Answer: A. Plants taking in carbon dioxide for photosynthesis
46. Which example shows interaction between the geosphere and biosphere?
A. Plant roots growing through soil
B. Water evaporating from an ocean
C. Clouds forming in the atmosphere
D. Sunlight reaching Earth
Answer: A. Plant roots growing through soil
47. Which human activity can disturb natural Earth-system cycles?
A. Deforestation
B. Sustainable forest management
C. Rainfall
D. Natural decomposition
Answer: A. Deforestation
48. Deforestation can directly affect:
A. The carbon cycle and water cycle
B. Only the rock cycle
C. Only the movement of planets
D. Only ocean tides
Answer: A. The carbon cycle and water cycle
49. Which action can help maintain the balance of Earth’s systems?
A. Excessive burning of fossil fuels
B. Large-scale deforestation
C. Conservation of forests and natural resources
D. Increasing pollution
Answer: C. Conservation of forests and natural resources
50. Why is understanding Earth as a system important?
A. It helps us understand how different Earth processes and living organisms are interconnected
B. It proves that Earth has only one component
C. It shows that humans do not affect Earth
D. It shows that energy and matter do not move through Earth systems
Answer: A. It helps us understand how different Earth processes and living organisms are interconnected