Water in the surface zone of the ocean is, for the most part depleted of oxygen the coldest the densest the saltiest well-mixed

Water in the surface zone of the ocean is, for the most part well-mixed.

Zones are also known as layers. Ocean is divided into five layers:
Epipelagic zone (The sunlight zone), Mesoplagic zone (The Twilight zone), Bathypelagic zone (The midnight zone), Abyssopelagic zone (The Abyss) and Hadalpelagic zone (The trenches).

When a virus infects a host cell, it uses the cell's machinery to make copies of its own genetic material in a process called replication. finally, during the process of self-assembly, that protein shell and the copies of the virus's genetic material are assembled into new viruses.