here's what it says from the book:
"Symbiosis speaks to the interactions of different organism living in close association. Typically assumed to be favourable for both parties, there are in fact three classifications of symbiotic relationships:
1. Mutualism, wherein both organisms benefit
2. Commensalism, advantageous to one organism and neutral to the other
3. Parasitism, in which one organism profits at the expense of the other