What is an ecosystem? Give an example.

Give a geographical reason for each of the following:
(i) Earth is a habitable planet.
(ii) From space Earth looks blue.
(iii) Water bodies reduce the day-night temperature variations.

You have gone from Delhi to Arunachal Pradesh on a study tour with your school during the winter vacation. As you woke up in the morning at 6 o'clock, you noticed the sun has risen whereas at Delhi sun rise is around 7.30 a.m. Similarly around 4.30 it was sunset while sunset is around 6 p.m. in Delhi. What do you think could be the reason for the sun rising and setting earlier than Delhi? Which feature of the earth can you relate to from this?

The earth depends upon the sun for its energy. Imagine a day, when the sun would not rise. Write down the consequences for the earth and its inhabitants.