Petroleum is mineral oil, organic in origin, and occurs in the pore spaces of sedimentary rocks. It...
physical
Coal, comprising mainly carbon of vegetative origin, is one of the oldest forms of power. It provided...
Minerals are natural, chemical substances which make up the rocks of the earth’s crust. They have certain...
In the history of mankind perhaps the most disastrous eruptions were those of Mt. Vesuvius, Mt. Krakatoa...
In tropical seas many kinds of coral animals and marine organisms such as coral polyps, calcareous algae,...
Lakes are amongst the most varied features of the earth’s surface. They occupy the hollows of the...
An island is a piece of land surrounded on all sides by water. It may occur individually...
A careful examination of the lakes of the world will reveal their immense human significance. In countries...
An earthquake is defined as a violent tremor in the earth’s crust which sends out a series...
The land of West Africa consists of contrasting kinds of physical environment. The forest environment differs from...
