Scientists believe that humans arrived on Earth during which Period?
What evolutionary development do scientists think occurred in the Cambrian period that gave rise to more complex fish?
Could you take a pregnancy test even if you've had your period but your're having pregnancy symptoms?
The theories are evolution deal with the fact that every being on the planet today came from a now-extinct species. This goes for humans as well. Scientists believe that humans evolved from now-extinct mammals during the Late Cretaceous period. Evidence proves people came from a member of the gibbon family.
Our solar system has, we believe, existed for about 4.5 billion years. Dozens, possibly hundreds, of planets probably formed about the same time as the Sun did. During the early period of the solar system, scientists believe that there was a period of massive collisions between planets and other forming bodies. One of these, a body perhaps as large as Mars, is believed to have collided with the early Earth and the debris coalesced in…