Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
Iron weighs more after it rusts.
68
For every gallon of sea water, you get more than a quarter pound of salt.
45
One ragweed plant can release as many as one billion grains of pollen!
51
Indoor pollution is 10 times more toxic than outdoor pollution.
62
The banana plant cannot reproduce itself. It can be propagated only by the hand of man.
155
The brain case [of Neanderthals] on the average was more than 13 percent larger than that of the average of modern man
61