Question

How did the first cells on the earth manage to survive in an atmosphere that lacked o2?

Answer 1

the first cells of earth managed to survive as some were photosynthetic and others were anaerobic

Answer 2

Answer:

$\\ the \: first \: cells \: on \: the \: \\ earth \: manage \: to \: survive \: in \: an \: atmosphere \: that \: \\ lacked \: o 2 \: by \: switching \: \\ over \: to \: anaerobic \: \\ respiration$