Answer:
Most economists recognize three factors or production: land, labor, and capital.
Of these, land is the hardest to change because it has a fixed supply (there is a definite amount of land available on earht).
Capital is the second more mobile, although some forms of liquid capital like cash, can be even more mobile than labor.
And labor is usually the most mobile and easiest to change (not always), because people often change jobs, and move in specific segments of the labor market.