Why does an electron have an opposite charge and a smaller mass to a proton

If a plot weight (in g) vs. volume (in ml) for a metal gave the equation y= 13.41x and r^2=0.9981 what is the density of the metal?

In 2002, the rare earth elements mine in mountain pass, california was closed because

What term is applied to a scientist who studies ancient life, including animal and plant fossils a. anthropologist b. dendroclimatologist c. geophysicist d. paleontologist