NCERT 5th Class (CBSE) Social Science: Our Environment

Question: What are the four spheres of the environment?

Answer: The four spheres are:

1. Biosphere
2. Atmosphere
3. Hydrosphere
4. Lithosphere

Question: List the importance of the hydrosphere?

Answer: The hydrosphere is the sphere of water and is very important for the existance of life on earth. It includes all the water bodies found on earth.

Question: Explain the water cycle?

Answer: Water is constantly in motion due to evaporation, condensation and precipitation. During the day time when it is very hot, water evaporates from rivers, lakes, oceans etc and rises as water vapor into the atmosphere on cooling, this water vapor change back into water droplets and falls on earth in the rain. This entire process of change from one form to another is known as the water cycle.

Question: Name the gases found in the atmosphere?

Answer: The gases found in the atmosphere are:

1. Nitrogen – 78%
2. Oxygen – 21%
3. Carbon dioxide – o.o4%
4. Hydrogen
5. Argon – Rare gases or found in traces
6. Kypton – Rare gases or found in traces
7. Helium – Rare gases or found in traces

Question: Why is the biosphere so important?

Answer: The biosphere includes those parts of the hydrosphere, atmosphere and lithosphere where living organisms are found and this layer makes living on earth possible. That is why biosphere is so important.