Define the following terms:
(a) Birth rate.
(b) Death rate.
(c) Population density.
(d) Exhaustible resource
(e) Rate of growth of population

(a) Birth rate.
The number of live births per thousand of population per year.

(b) Death rate
The ratio of deaths to the population of a particular area or during a particular period of time, usually calculated as the number of deaths per one thousand people per year.

(c) Population density.
Population density is a measurement of population per unit area or unit volume; it is a quantity of type number density. It is frequently applied to living organisms and most of the time to humans. It is a key geographical term.

(d) Exhaustible resource
Resources of which a finite quantity is in existence. Oil and gas are exhaustible and be all sucked up and burnt up. A natural resource that cannot be increased by the natural forces of the environment is called exhaustible natural resources.

(e) The rate of growth of population
The "population growth rate" is the rate at which the number of individuals in a population increases in a given time period, expressed as a fraction of the initial population.