Final answer:
The word "evolution" or a form of it is used multiple times in Darwin's book, "On the Origin of Species." The usage frequency varies throughout the book, appearing in different sections and chapters where Darwin discusses the theory of evolution, natural selection, and supporting evidence.
Step-by-step explanation:
The word "evolution" or a form of it is used multiple times in Darwin's book, "On the Origin of Species." While it is not mentioned on every page or in every paragraph, it is not used only once in the entire book either.
It appears in different sections and chapters, where Darwin discusses the theory of evolution, natural selection, and evidence supporting evolution. The frequency of its usage varies throughout the book.