Chapter 13 Solutions — Our Home: Earth, a Unique Life Sustaining Planet

Keep the Curiosity Alive

1. 1.
   What is one major reason Mars cannot currently support life like Earth?

   • (i) It has too many volcanoes.
   • (ii) It is too close to the Sun.
   • (iii) It lacks a thick atmosphere and liquid water.
   • (iv) Its magnetic field is too strong.
2. 2.
   Which of these is an example of geodiversity?

   • (i) Variety of bird chirping in a forest.
   • (ii) Different landforms like mountains, valleys, and deserts.
   • (iii) Changing weather during monsoons.
   • (iv) Number of different types of fish in a pond.
3. 3.
   If the Earth were smaller with the same density, what might happen to its atmosphere?

   • (i) It would become thicker and hotter.
   • (ii) It would escape into space due to weaker gravity.
   • (iii) It would become frozen.
   • (iv) It would cause stronger winds.
4. 4.
   In sexual reproduction, why are offspring different from their parents?

   • (i) They grow in different climates.
   • (ii) They eat different food.
   • (iii) They acquire new instructions after birth.
   • (iv) They get mixed instructions (genes) from both parents.
5. 5.
   You notice tiny green plants growing in cracks on your school wall after the monsoon. Where do you think the seeds came from? What conditions helped these plants grow there?
6. 6.
   A city has recently cut down a large patch of forest to build new roads and buildings. Discuss the possible effects this could have on the local climate and biodiversity. How might this affect water availability or quality in the area?
7. 7.
   A friend says, "The Earth has always had climate changes in the past, so today's global warming is nothing new." How would you respond using what you've learnt in this and other chapters of your science book?
8. 8.
   Imagine Earth's magnetic field suddenly disappeared. What kinds of problems could arise for life on Earth? Explain.
9. 9.
   You are tasked with designing a new settlement for humans on Mars. Name three things you would need to recreate from Earth to support human life there. Which of these do you think is the hardest to replicate, and why?
10. 10.
    In a village, the temperature has been increasing and rainfall has become unpredictable over the past few years. What could be causing this change? Suggest two ways the village could adapt to these new conditions.
11. 11.
    If there were no atmosphere on the Earth, would it affect life, temperature, and water on the planet? Explain.
12. 12.
    Discuss five examples of vegetative propagation.