Those higher elements were produced in stars and supernovae. All of this is dependent on the expansion rate of the universe, which is still unknown. The elements created between the first and third minutes of the Big Bang included Helium 4, Hydrogen 2, Hydrogen 3, neutrons, Lithium 7, and Beryllium 7. Helium 4 yielded metal poor dwarf emission-line galaxies. Scientists across the field are more or less in agreement with this theory.
Observation agrees with theory that the universe was very hot and very uniform.