Library Passwords Doc
Britannica
World Book
Science in Context
Twig Videos
Quora Article: "Living on Mars Might have Benefits - and Risks - to Humans"
Space.com Article: "Weightlessness and its Effect on Astronauts"
NASA Article: "Twins Study"
Science magazine: "Humans are still evolving..."
BBC Earth: "What will humans look like in a million years?"
The Plight of the Cheetah: Video
