Why are three fonts used in the text?


April 2019: for reasons related to the American Disabilities Act, we are phasing out the styling below, topic by topic over time.

These fonts are used to weigh statements or phrases by 3 “Levels of Certainty”. This reduces the number of qualifiers needed in the text, and avoids misunderstandings.

This is TRUE, based upon currently known information.
This is LIKELY, based upon available information.
Everything else, including uncertain or speculative information.


Humans shared a common ancestor with Chimpanzees and Bonobos, who are our closest living relatives. This common ancestor likely existed 6-7 million years ago. It is unclear whether the common ancestor was more similar to chimpanzees or bonobos, or equally different from both.