Answer:
Activity.
Explanation:
Aging may be defined as the process of growing old with the increasing age. The shortening of telomeres in human being is considered as the main cause of aging.
Activity theory of aging states that the aging is successful when older individual is healthy and perfectly maintains the social interactions. Bea is around 70 and is quiet healthy and active. She maintains the social interaction with other individuals. This, determines the activity theory of aging.
Thus, the answer is activity.