Question

Where did all the antimatter go? ... ​

Answer 1

All the matter and antimatter particles should have annihilated with each other since then, leaving only photons, but somehow one matter particle in a billion or so has survived to create the universe as we know it.

Answer 2

Answer:

All the matter and antimatter particles should have annihilated with each other since then, leaving only photons, but somehow one matter particle in a billion or so has survived to create the universe as we know it.