How does organizing history by theme illustrate continuity?

a.)It explains noticeable and influential gaps between eras.

b.)It shows how past events influence subsequent events.

c.)It highlights how events within eras lead to subsequent events.

d.)It illustrates the major eras over a given period of time.

The processes that develop from Prehistory to the conformation of the current world, occur in a historical time that covers millions of years, so it is necessary to organize it in periods to be able to know and study it. There are different ways of establishing periods of humanity's past; however, in the western countries a periodification centered on the processes in Europe is used, which is the cradle of the Christian-Western civilization.

The periods in which history is divided have been established mainly by historians, who select some milestones or aspects considered relevant to differentiate one era from another. On occasion, the transition from one epoch or period to another occurs slowly and gradually, so these changes are imperceptible to people; in other occasions, events of great impact occur in society that generate a profound and rapid change, as occurs in the cases of revolutions.