5. Mention two important features of earth that make it a planet suitable for life.
What is meant by hydrosphere?
What is meant by lithosphere?
What is the importance of the atmosphere of the earth?
How is the atmosphere of the earth different from that of other planets ?
What is a food chain ?
Answers
Answer:
1)It is the layers of gases surrounding the earth that consists of exosphere, thermosphere, mesosphere, stratosphere and troposphere. The air content and favourable atmospheric pressure also supported life of most creatures. The air content of carbon dioxide on the Earth is less than that of planets like Venus and Mars.
2)A hydrosphere is the total amount of water on a planet. The hydrosphere includes water that is on the surface of the planet, underground, and in the air. A planet's hydrosphere can be liquid, vapor, or ice. On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers.
3)The lithosphere is the solid, outer part of the Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. It is bounded by the atmosphere above and the asthenosphere (another part of the upper mantle) below
4)The atmosphere protects living things from the Sun's most harmful rays. Gases reflect or absorb the strongest rays of sunlight (Figure below). The atmosphere shields Earth from the most harmful solar rays.
5)The main difference between the Earth's atmosphere and the one of other planets (such as Venus and Mars) is that about 21% of it is composed by oxygen. Oxygen is a key element to sustain any complex life form on the planet. Both produce oxygen by means of photosynthesis.
6)A series of organisms in which each creature eats the one below it in the series and becomes a source of food for the organisms above it
Explanation:
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