Define the biosphere, in the chapter's own words.
Hint. The definition includes both the living things themselves and where they live.
✦ 'All living beings, along with the places where they live, make up the biosphere. This includes land, water, and air, where life interacts with its surroundings to survive and grow.'
Connect this chapter's biosphere section back to Chapter 12's food chain concepts — name the three roles the chapter recaps.
Hint. The chapter deliberately reuses vocabulary from the ecology chapter rather than introducing new terms.
✦ The chapter recaps: plants make food through photosynthesis (producers), animals eat plants or other animals (consumers), and decomposers break down dead matter and return nutrients to the soil — the same three roles established in Chapter 12, since all three are now framed as part of the biosphere working together as a system to support life.
Explain, using the chapter's own forest-cutting example, why the 'importance of balance' section says even a small change can have wide-reaching effects.
Hint. One specific human action is traced to several different consequences at once.
✦ The chapter states 'even a small change in one part — like cutting down a forest — can impact rainfall, soil, air quality, and the animals that live there,' since forests interact with the atmosphere, hydrosphere, geosphere and biosphere simultaneously. Removing a forest doesn't just remove trees — it disrupts the whole interconnected system of rainfall patterns, soil retention, air composition, and habitat for the animals that depended on it.
Why does the chapter compare Earth to 'a giant teamwork project,' and what practical conclusion does it draw from this comparison?
Hint. The comparison leads directly to a statement about why environmental protection matters.
✦ The chapter describes Earth as 'a giant teamwork project between nature, weather, and life itself... a vast, living system where land, air, water, and living things support and affect one another,' because life survives not through any single factor but through everything working together in balance. From this, the chapter draws the practical conclusion that 'preserving and protecting clean air, water, soil, and all forms of life isn't just important but essential for keeping Earth healthy for the future.'
Name the four Earth systems (spheres) introduced across this chapter, and state which one is composed of living things.
Hint. Four systems, one per major theme of section 13.4 plus the atmosphere from earlier sections.
✦ The four Earth systems are the atmosphere (air), hydrosphere (water), geosphere (the solid rocks, soils and minerals of Earth), and biosphere (all living beings and the places where they live). Of these four, only the biosphere is composed of living things — since the other three are non-living systems that the biosphere depends on and interacts with.
Solutions written by the tuition.in editorial team and checked against NCERT Curiosity — Textbook of Science for Grade 8, Chapter 13 (hecu113.pdf), Reprint 2026-27, pages 210-228. Questions are referenced from the NCERT textbook for identification.
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