Why are the average masses on the periodic table rarely whole numbers even though it is impossible for an atom to weigh a fraction of an a. m.u.?

Why is earth's outer core hotter than earth’s oceanic crust? earth’s oceanic crust is denser than earth’s outer core is. earth’s oceanic crust has lava flowing from the mantle. earth’s outer core has a composition of solid iron and nickel. earth’s outer core is deeper within earth than oceanic crust is.

Some scientists argue that global warming is related to buming fossil fuels to produce energy o increased use of fertilizers loss of forested areas a of the above

If garbage is left on the street flies in microbes can arise from nothing to feed on it true or false