Interesting facts about bacteria. 1) After the rain was, the earth has the smell. You can smell this aroma, because some bacteria, who live in the ground, produce the organic matter, which has this smell. 2) The bacteria haven't changed their appearance but only their internal structure during evolution. 3) Two kilogram of bacteria live in human body. The most of them live in our intestines. 4) Formerly scientists thought the appendix is a rudiment. But now they say appendix is an organ of immune system, because bacteria live in it. 5) In time of diseases a lot of bacteria perish in the intestines. And bacteria, who are in appendix, go in intestine.