Answer:
the effort of individuals and a society (and its public policies) that enable it
Step-by-step explanation:
Social mobility is a sociological theory that enables a person to maintain the status in the society when that person reaches at a very high position and earns a lot of respect and wealth.
It is the individual's hard work and effort that enables them to move up in the social status ladder to gain respect, name and fame.
Social mobility is also called as Social hierarchy where an individual move up or move down in the social hierarchy order.
Thus the answer is
the effort of individuals and a society (and its public policies) that enable it