Petroleum is called mineral oil. It is an inflammable mixture of oily hydrocarbons. Like coal, petroleum is also a fossil fuel. It is generally taken that the oil has been derived from buried marine organisms. In areas where the sedimentary strata have been folded, most of the oil comes from anticlines rather than synclines.
An isohyet or an isohyetal line is a line that joins places of same rainfall on a map within a given time period. A map of isohyets is also known as an isohyetal map.
EXAMIANS