Grids and variables are used to find coordinates. Latitude and longitude coordinates
Subsistence farming, form of farming in which nearly all of the crops or livestock raised are used to maintain the farmer and the farmer's family, leaving little, if any, surplus for sale or trade. Preindustrial agricultural peoples throughout the world have traditionally practiced subsistence farming<span>.</span>
I would say by using a telescope to look into the sky
Mountains are created when two plates collide. When the plates converge or slide underneath each other the heat causes melting of the crust and volcanoes appear. When they cool off they become islands.
