He wild horse was once short and slow to run from predators, yet today it is tall and runs very quickly, thus making it able to escape from predators. What caused this change?

The growth and development-

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.