From the following which is the optimum distance between sun and earth.

What is the average speed of the revolution of the Moon around Earth?

One stadia is equal to -------- metres.

Which is the hottest planet in the solar system?

The first attempt of estimating the size of the earth was made by whom?

The layer of water on the surface of Earth is called --------

From the following which indicates the percentage of water present on earth surface?

The layer of rocks which forms the surface of earth is called -----------

Which is the richest gas present in Earth?

Polestar appears vertically overhead at the ----------- .