Charles Darwin theorized that all species undergo a natural cycle of evolution in order for the species to survive and thrive within its given environment. In the case of a catastrophic event, Mother Nature will naturally find a way to support life and the organisms that are within her care.
The best answer would most likely be genetics or genetic theory.
There were many doubts about Darwin's theory because Darwin could not yet describe the mechanism of inheritance. Mendel's work on inheritance was already published, 2 years earlier, but this eluded Darwin. It was only till after Darwin's death that the science of genetics came about.
This union brought about the "modern synthesis," a theory that proposes that both genetics and natural selection is a result of evolutionary changes.
Are you looking for an explanation or the equation?
A typical adult has a blood volume of approximately 5 liters.
