Answer:
Personal achievements
Step-by-step explanation:
While class systems are based in part on a person's birth, or class of their parents, an important difference between caste and class systems is that class systems also incorporate the concept of personal achievements in determining one's social position.
In caste system, an individuals social class is already determined at birth, whether poor or rich. However, in class systems, an individuals achievement is important in determining his/her social class. For example, a janitor can be hardworking, gets educated and become successful and thus changing his/her social class, while a child born into affluence may be wasteful and end up poor thus experiencing a downward social mobility.