Organisms tolerate only limited variation in environmental osmotic concentration.
a) euryhaline
b) stenohaline
c) osmoregulator
d) osmoconformer

stenohaline

Explanation:

Stenohaline are organisms usually the fish, like goldfish which cannot tolerate fluctuations of their environment to salinity. They can die due to high or low salinity in their environment. Most fo this organisms are concormers and therefore their body do not change in osmolarity concentration due to salinity.

a symbiotic relationship with the mitochondria