Mother Nature. She does the difficult work. Humans - we do the farming, gathering, and distilling.
This micrograph shows the very small cells that produce and store essential oils. They are called Trichomes (pronounced TRI-combs).
Simply touching a Trichome cell will release the essential oils. When you touch an aromatic plant (like lavender, spearmint, peppermint, oregano, thyme, rosemary, etc) some of the essential oil is released from the Trichomes. You can smell the oil on your hands. You can smell it in the air.