I think I have just figured out how every single thing on this planet is connect from the beginning of time.
Imagine you and one other person are together in a room. When you breath in air is drawn into our body to our lungs. The lungs oxygenate our blood and then the air is breathed back out. This happens about 12-18 breaths per minute. This is also happening when the other person in the room breathes.
As you know, germs can be transferred by people breathing showing quite clearly that what comes out of one persons lungs can be transferred to another person via breath. If germs can be transferred this way then surely somewhere in that breath you exhaled there is some microscopic atom that was part of your DNA
So when I breath I breath in air that has been in another person. OR when I breath out my DNA I also breath in another persons DNA.
Now imagine how much of the air is breathed in and out of our lungs every day. This is the same air that has been on this planet since the beginning.

"Hold on" I hear you say.
"air is recycled by trees"
Yes this is true. Everyday the carbon dioxide breathed out of our bodies is cleaned and recycled by trees and plants through photosynthesis. This is the process where a plant or tree uses the sunlight to turn carbon and water into nourishment to help it grow. (we will talk about this in a minute)