"An older woman retires and completely changes her life. She is no longer raising children or working. However, she joins the YWCA to swim every day. She serves on the Friends of the Library board. She is part of a neighborhood group that plays Bunco on Saturday nights. Her situation most closely illustrates the theory."

Actiivity Theory

Explanation:Activity theory is a conceptual framework originating from the socio-cultural tradition in Russian psychology. The foundational concept of the framework is “activity”, which is understood as purposeful, transformative, and developing interaction between actors (“subjects”) and the world ("object"). The framework was originally developed by the Russian psychologist Aleksei Leontiev (Leontiev 1978; Leontiev 1981). A version of activity theory, based on Leontiev’s framework, was proposed in the 1980s by the Finnish educational researcher Yrjö Engeström (1987). Currently, both Leontiev’s and Engeström’s variants of activity theory, as well as their combinations, are being widely used interdisciplinarily, not only in psychology, but also in a range of other fields, including education, organizational learning, and cultural studies.

answer; collectivism;

it might look like that the ideal way to research the health effects of trans fats is through a controlled experimental feeding trial. but these kinds of trial have several important limitations that the researcher must look into:

short in duration (this factor usually checks up on the intermediary risk factors rather than the actual outcomes of the disease)

limited dietary changes

only makes use of healthy participants