Population structure in Africa.

Population structure is the composition of population of a given area at a particular time.  This structure can be analysed in terms of age and sex groupings and is represented by population pyramid/ age-sex pyramid. It is important to look at the population structure because the make up of the population by its age and sex together with life expectancy has implications on future growth, economic development and social policies of that country.
The age –sex pyramid is simply a bar diagram of the population of a specific area, constructed in one , five or ten year age groups with males one side and females on the other.  This usually take s the form of a pyramid, with the base representing the youngest age group ant the apex the oldest.  The horizontal bars are each drawn proportional in length to either the percentage of the population that they represent to the actual number of people on the age group.
A high birth rate and therefore the population contains many young people hence high dependency ratio
Rapid fall In each upward age group due to high death rates
Short life expectancy.
However, there is a slight fall in death rate in stage 2 as there is a large number of people living in the middle age with slightly reduce in the dependency ratio.