Mountains generally occur in a chain or line called a ___________.

__________ covers about one fifth of the total area under oceans and seas.

___________ spreads over almost one third of the globe.

Which is the longest river in the world?

The vast areas of water surrounding the land masses on the earth are called ____________.

Bay of Bengal is the example of _____________.

____________ are thickly populated.

Smaller land masses are called __________.

Heights of land masses are measured from the __________.

Low lying,flat surfaces with very gentle slopes are called __________.