With regard to uniform temperature and the isotropy problem, why would we expect different temperatures (non-uniform) if the universe had expanded more slowly (rather than by “inflation\)?
See above question. If the universe had expanded since the Big Bang without ever undergoing a period of rapid expansion, well-separated regions in the sky would not have been in thermal equilibrium with each other at the time when they emitted CMBR. In that case, we would expect them to look much more different than they are observed to be, since they evolved independently. Quantitative models without inflation predict much larger temperature and density fluctuations, in contrast to the extremely uniform temperatures actually observed. The explanation is inflation: if the universe suddenly blew up enormously, points on opposite sides of the sky would indeed have been in thermal equilibrium.
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