The Riftia/bacterium symbiosis would then be refered to as a "mutualistic symbiosis" a relationship in which both partners benefit versus just symbiosis.
(The Riftia/bacterium symbiosis; would be refered; as a "mutualistic symbiosis; T:then) (both partners; benefit; versus just symbiosis; L:a relationship)
The Riftia/bacterium symbiosis both partners
would be refered benefit
as a "mutualistic symbiosis T:then
versus just symbiosis L:a relationship