Answer:
Pangaea
Step-by-step explanation:
The Earth's crust is not one solid block but is made of different segments called tectonic plates. At one point it started to break apart. The land mass was present around the Paleozoic and Mesozoic eras. This land mass was called Pangaea
As a result all the water on Earth was a part of an ocean called Panthalassa. The concept of the one land mass and one water mass was proposed be Alfred Wagner.
Hence, the statement here is referring to Pangaea.