I also made a comic about this topic a while ago:
https://psfforum.com/index.php?PHPSESSID=f0afcf0c5f11836400762ac5862904c1&topic=2600.msg285442#msg285442WARNING: Spoilers ahead!2B was created by other androids, nothing that interesting about it.
Also, these androids can breathe, cough, get chocked, cry, spit, bleed and even get nauseous and throw up as a result. It's not too farfetched to think that they can also sneeze, even if... sadly, no ever sneezed in the game.
[spoiler]By the time the game story happened, humanity has been extinct for a really long time. A terrible epidemic killed all of humanity and these androids were originally meant to replace it. Originally they were supposed to also store people's souls and memories but the androids started developing their own souls and personalities and with the time they overthrown the humans souls stored inside them.
Humans could not fix this problem in time and they all perished as a result. Now all androids live without purpuse on Earth, as their original intent was to serve humanity.
In short: they have so many human-like features because they were meant to replace humanity. [/spoiler]