This is why active organisms such as human beings have evolved elaborate circulatory and respiratory systems to bring oxygen to their cells.
(This; is; why active organisms such as human beings have evolved elaborate circulatory and respiratory systems) (human beings; have evolved; elaborate circulatory and respiratory systems) (human beings; to bring; oxygen; to their cells)
This human beings human beings
is have evolved to bring
why active organisms such as human beings have evolved elaborate circulatory and respiratory systems
elaborate circulatory and respiratory systems
oxygen to their cells