Keep the Curiosity Alive (Page 226-227)
Q1. Why Mars cannot support life currently?
Answer: (iii) It lacks a thick atmosphere and liquid water. Explanation: While Mars is in the habitable zone edge, its atmosphere is too thin to trap heat or allow liquid water to remain stable on the surface.
Q2. Example of Geodiversity
Answer: (ii) Different landforms like mountains, valleys, and deserts. Explanation: Geodiversity refers to the variety of earth materials and forms (rocks, soil, landforms).
Q3. Smaller Earth Atmosphere
Answer: (ii) It would escape into space due to weaker gravity. Explanation: Gravity is determined by mass. A smaller/lighter Earth would have less gravity, unable to hold onto gas molecules.
Q4. Variation in Sexual Reproduction
Answer: (iv) They get mixed instructions (genes) from both parents. Explanation: Sexual reproduction combines genetic material from two sources, creating unique combinations.
Q5. Plants in Wall Cracks
Answer:
- Source: Seeds likely arrived via wind or bird droppings (birds eat fruit and excrete seeds).
- Conditions: The crack trapped a small amount of soil/dust and moisture (from monsoon rain), allowing the seed to germinate.
Q6. Deforestation Effects
Answer:
- Climate: Trees release water vapor (transpiration). Cutting them reduces local humidity and rainfall, potentially making the area hotter (Urban Heat Island effect).
- Biodiversity: Habitat loss leads to animals/birds leaving or dying.
- Water: Tree roots hold soil and help groundwater recharge. Without them, rainwater runs off causing floods and soil erosion, reducing groundwater availability.
Q7. “Climate Change is Nothing New”
Response: “While Earth has changed in the past, current global warming is happening much faster due to human activities (burning fossil fuels). Natural cycles take thousands of years; we are seeing changes in decades. This rapid change doesn’t give life enough time to adapt.”
Q8. Magnetic Field Disappearance
Answer: If the magnetic field vanished:
- Radiation: Harmful solar wind and cosmic rays would bombard the surface, causing cancer and DNA damage.
- Atmosphere Loss: The solar wind would slowly strip away the atmosphere (like it likely did on Mars).
- Navigation: Animals that use magnetic fields to migrate (birds, turtles) would get lost.
Q9. Mars Settlement Design
Three Essentials:
- Oxygen/Air Supply: Mars has no breathable air.
- Liquid Water: Must be extracted from ice or recycled.
- Shielding: Protection from radiation (since Mars has no magnetic field/thick atmosphere). Hardest to Replicate: A breathable atmosphere/Shielding on a planetary scale. We can build domes, but terraforming the whole planet is currently impossible.
Q10. Village Climate Adaptation
Causes: Deforestation or Global Climate Change. Adaptations:
- Rainwater Harvesting: To store water during unpredictable rain.
- Crop Diversification: Planting heat-resistant or drought-resistant crops.
Q11. No Atmosphere?
Answer:
- Temperature: Extreme swings (Boiling day, Freezing night).
- Water: Would boil away into space immediately.
- Life: Impossible (No oxygen, no pressure, deadly radiation).
Q12. Vegetative Propagation Examples
- Potato: Grows from “eyes”.
- Ginger/Turmeric: Grows from rhizomes.
- Rose/Hibiscus: Grows from stem cuttings.
- Bryophyllum: Grows from leaf buds.
- Strawberry: Grows from runners.