Answer:
Euhaline ⇒ Polyhaline ⇒ Mesohaline ⇒ Oligohaline
Explanation:
Let's first define each of these levels:
- Polyhaline: a category of salinity that has medium-high levels of salt
- Mesohaline: a category of salinity that has medium levels of salt
- Oligohaline: a category of salinity that has low levels of salt
- Euthaline: a category of salinity that has high levels of salt
Now, we can order these in decreasing order of salinity:
Euhaline ⇒ Polyhaline ⇒ Mesohaline ⇒ Oligohaline
