How does evolution lead to both the diversity and the unity of life?

Simple. All of the millions of different life forms (the diversity of life) have come about by natural selection, whereby random mutations in the genes have either succeeded or failed. But all life can be traced back to a common single-celled origin. Thus we have the unity of life where we (possibly) share more than 50 % of our DNA with a crocodile.eg:analogous organs, homologous organs.

Ilike to eat pears ya nah wha im sayin b? shout out to all my pears b.

Air enters through the nose (and sometimes the mouth), moves through the nasal cavity, the  pharynx, the  larynx, enters the  trachea, moves through the  bronchi  andbronchioles  till the alveoli.