He model of personality development states that with time and age people become more adept at interacting with their environment in ways that promote increased stability in personality

The cumulative personality  model of personality development states that with time and age people become more adept at interacting with their environment in ways that promote increased stability in personality.
 This model integrates the findings of empirical research on the development of personality traits with the theoretical and empirical models derived from identity research in an attempt to explain the patterns of personality.

What the question i don't get it do u mean what she needs to do to auctually become one

The correct answer is a. when they started making tools that will them in cultivating lands, they could raise crops and that made them attached to one place for a longer period of time. after that, they started domesticating animals and building their own permanent settlements that resemble the ones we have today.