The answer is A: The development of the first mathematical system of perspective
They work for dirt cheap, and work hard because they want to keep the work they receive, an immigrants usual only hope is a steady work whether or not they're illegal.
I believe the answer is professionalism.
Professionalism would also be translated as a set of skills that expected from someone at a certain job position.
In order to obtain those set of skills, Experiences and formal training are the most crucial factors to have.<span />
