Norma, a 68-year-old, has a few close friends. these friends are not a very diverse group, but they provide her with the emotional support she needs. her grandson, in contrast, has a large group of casual friends. these patterns are consistent with:

the socio-emotional selectivity theory

Explanation:

68-year-old Norma has diverse friends of her who provide  emotional support to her and her grandson has a large group of casual friends. Thus these patterns are consistent with the socio-emotional selectivity theory.

The  socio-emotional selectivity theory is theory given by Laura L. Carstensen who states that as people grow in age and matures they try to invest their time and resources at useful and emotional things. According to this theory elderly people select those things and try to spend time with people who will provide them emotional and moral support at times of need.

Thus the answer is ---

"the socio-emotional selectivity theory"

economic

if interdependence implies a two-way dependence, and if each partner is equally dependent on the other for success, then there is an equal commitment to the making the partnership successful. the advantage is sustainability of the relationship, the disadvantage is that decisions are "democratic" and therefore may take longer to reach and more likely to be a compromise (which is not always the best solution). as the interdependence moves away from equality, the decisions become more influenced by the more independent partner. in the extreme the relationship becomes more dictatorial and more like "master-slave". generally the relationship has less commitment in both directions and is more likely to be temporary.

if one generalizes (and one shouldn't), equity partnerships, which is probably what is implied by interdependence, can be slow to progress or change but durable. the extreme alternative, independent-dependent partnerships tend to be efficient but more fragile.

hope this but you will have to site your own evidence. : )