"moved about" or "roamed"
all the living creatures that lived in great numbers upon the earth
This refers to all the animals that move around on the ground in large groups.
who breathed the breath of life through their noses
Here "noses" represent the whole animal or human. AT: "everyone that breathed" (See: rc://en/ta/man/translate/figs-synecdoche)
the breath of life
The words "breath" and "life" represent the power that causes people and animals to be alive. (See: rc://en/ta/man/translate/figs-metonymy)
This refers to physical death.