viridian
No, it's a parallel.
Yes it does.
Vertical
"240 degrees east of the Prime Meridian" places you at 120 degrees west longitude.
prime meridean
Ante-Meridian; before midday; morning.
The Continent's it passes are Africa, Antarctica, and Europe
Three: Europe, Africa,and Antarctica.
It's a meridian, directly opposite the Prime Meridian.
Mexico, usa, Canada
western, its just barely on the left side of the prime meridean
At zero degrees longitude. Only on one side, the other side is the international date line.