91.   Scientists know for certain that the male hormone testosterone fuels the cancer once it is sparked.

92.   Scientists know much about sleep, but unlike, say, the facts of exercise or nutrition, the facts have not reached the laity.

93.   Scientists know that because as part of their job, they examine the stomachs of sperm whales and find the parrot-like beaks of squid.

94.   Scientists know that hormones often override judgment and common sense in many people.

95.   Scientists know that its habitat has diminished but not how many of the reptiles are left in the world.

96.   Scientists know that lymph nodes are a hot bed of viral activity early in infection.

97.   Scientists now know, with pinpoint precision, where in the brain nicotine works and why for most people it is so addicting.

98.   Scientists already knew that pollutants from fires in Asia could spread across the oceans, Gille said.

99.   Scientists already know a few things about Titan.