The word this” in paragraph 1 refers to ______.l

* Hướng dẫn giải

Dẫn chứng: One of these is the subtraction of water from the ocean by means of evaporation – conversion of liquid water to water vapor. In this manner, the salinity is increased, since the salt behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.