Why Do Men Have Nipples?
Answer: In the early stages of development, the fetus does not have a sexual assignment. Thus, the female and male bodies develop the same way giving both sexes the same set of sex organs, including nipples. Changes are only brought about with the effect of the genes, the Y chromosome and the hormone testosterone that masculinize the embryo. Testosterone promotes the growth of the penis and t*******s and gets rid of the vagina but because nipples are there before the real sex development begins they stay right where they are. So men, embrace and get to loving them.
Why the nipples stay and the vagina disappears, however, remains shrouded in controversy except for my girlfriend's claim that I would "look weird" without nipples...I'll have to agree.Source
How Much Bacteria Do We Have In Our Bodies?
Answer: On average, we each house 2 to 5 pounds of LIVING bacteria. That's (again with the American statistics) 8 to 20 Quarter Pounders worth of bacteria. Did someone say Mickey D's?Source
What Animal Engages In Sex Most Like Humans?
Answer: The Bonobo, a primate found exclusively in the Congo. Bonobos are the only non-human animal to have been observed engaging in all of the following sexual activities: face-to-face genital sex, tongue kissing, and oral sex.
They are also known to engage in homosexual behavior with females touching their genitals together and males engaging in an act called Ã¢ÂÂpenis fencingÃ¢ÂÂ (I think you can figure that one out for yourself). They'll even participate in orgies and sometimes incest.
Whoa there, we don't do that...
Ok, yeah we do. Perverts.Source
Why Do We Laugh?
Answer: This is a tough one and has no clear cut answer except that it is most likely a product of our evolution coming "from the panting behavior of our ancient primate ancestors. Today, if we tickle chimps or gorillas, they donÃ¢ÂÂt laugh Ã¢ÂÂha ha haÃ¢ÂÂ but exhibit a panting sound. ThatÃ¢ÂÂs the sound of ape laughter. And itÃ¢ÂÂs the root of human laughter."
It's also important to note that laughter is primarily a form of social interaction and that a major part of the evolutionary success of humans is that we're (I'm including you assuming that you're human) social creatures. So the fact that laughter in humans develops at 3.5 to 4 months, way before development in the ability to talk, suggests its true importance as a bonding tool.
Even when we laugh "at" someone and not "with" them, the intent seems to be to suggest that the person being laughed at is outside of the group and must conform. So just remember that the next time someone laughs at you for wearing that stupid shirt...they don't hate you, they just want you to join their group. But you'll say no, because who wants to be part of a group of assholes?Source