Misc: In 1990 ---------- Cafe opens in Las Vegas Nevada. ?

Questions

who, while working in cambridge, was the first to calculate, accurately, the density of the earth?

name the four groups of elementary particles, no commas, in alphabetical order?

one of the broad group of elementary particles, the boson, is also known by its more common name of?

who was the scourge of god?

who was the absolute dictator of the congo free state between 1890 - 1911?