Likewise, if the population consists of equal numbers of males and females, and if the females give birth to 3 children each (and the males 0), then the average birth rate of the population will be 1.5. With these basics we can now consider two simple models of population growth:
For most purposes scrolls have long been superseded by the codex book format, but they are still produced for some ceremonial or religious purposes, notably for the Jewish Torah scroll for use in synagogues.
The history of scrolls dates back to ancient Egypt. In most ancient literate cultures scrolls were the earliest format for longer documents written in ink or paint on a flexible background, preceding bound books; rigid media such as clay tablets were also used but had many disadvantages in comparison.