Without any information i would say the industrial revolution and the pollution that occured because of it
...of strict social stratification...
When considering a career, and the path to that career, it's important to take into account the average annual salary, the cost of the education, the length of the education, and the future of the industry you want to enter.
1: Community needs
2: Finances and accountability
3: Stereotyping
4: Accessibilty
