Answer:
Christianity and Buddhism believe in peace after death (heaven for Christianity and Nirvana for Buddhism). Both religions believe in consequences for your actions. (Reaping what you sow: Christians and Karma: Buddhists)
Differences:
Buddhism does not believe in a soul, while Christianity does
Christians Pray to God, Buddhist do not
When you die you go to heaven or hell, but for Buddhists there are ranks to Nirvana.
D). Vast empires.
Classical civilizations developed vast empires, whereas early river valley civilizations did not.