It is found that birds have evolved in the Mesozoic Era from a a group of theropod dinosaurs. the most close relative of modern day bird was supposed to be a primitive bird known as Archaeopteryx. In a recent study conducted by UCMP Berkeley, birds have common ancestors from the theropod lineage. More specifically, lizard-hipped dinosaurs are ancestors of birds.
The scientist will add up the mass of the protons and mass
of the neutrons to come up with the approximate mass of atom because protons
and neutrons is what consist of the atoms. Therefore, in order to have the approximate
mass of an atom, adding the mass of protons and neutrons will give the result.
