Page 102 - Social Studies 4

At the beginning, all the planets were very hot. The earth was with an
ocean of hot magma. After millions of years, they started cooling down.
Later comets (Icy bodies revolve around the sun) caused the presence of
water as they hit the earth.

The low lands became oceans, lakes, seas or rivers and the high lands
became hills and mountains.

Gradually, virus and bacteria appeared in the water of the ocean. Similarly,
plants appeared in the water and later in the land. Similarly, animals
appeared first in the water and then in the land.

After this, the diversification process began. This process has been
modifying the creatures on the earth to be fit for the time and the
environment.

Humans are considered as the latest modifications of the diversification
process.

98 Megha's Integrated Social Studies - 4