This is known as parasitism.
In biology, parasitism is a relationship between species, where one organism, the parasite, lives on or in another organism, the host, causing it some harm, and is adapted structurally to this way of life.
They're called endorphins!
I love texting the unknown
Here you go <span>Mitochondrial DNA can be traced for generations.</span>
Index fossils (also known as guide
fossils, indicator fossils or zone
fossils) are fossils used to define
and identify geologic periods (or
faunal stages).
