The relationship between a parasites and host is called parasitism.
Oeganism that lives on another organism and obtain food is called parasites.
Organism obtain food from the dead organic matters are called saprophytes.
Types Ectoparasites -Lives on external surface of host and draw nutrition.

Endoparasites – grow inside the hostcell Destructive parasites -kill the host and draw nutrition.

Balance parasites – draw nutrition without killing the host
Faculative parasites – usually saprophytic but under certain conditions became parasites.
Faculative saprophytes -usually parasites but under certain conditions became saprophytes.