Cultural traditions are a unified collection of ideas and customs that are unique or specific to certain societies or regions of the world. They are often called “syncretic” which means a mix of cultural traits from a variety of sources, or “dynamic” which means subject to change over time. You could say that a “dynamic” tradition is likely to change in the future but this is not as close to the correct meaning as the other answer choice.

The Caste System is a part of Indian and Hindu culture that affixes an individual within a certain social group, from birth. The group an individual is a part of can affect anything from the type of work he can get, where he can live, whom he can marry, and how other people treat him. A Hindu can move up the Caste System by living virtuously and attaining good karma. After several lifetimes of good karma a Hindu can achieve eternal salvation and emerge from the cycle of life.

"Eugenics" is a set of beliefs and practices aimed to improve the genetic quality of human populations through selective breeding and sterilization. "Genetics" refers simply to inherited traits or characteristics or the study of such traits. "Abstinence" refers to the practice of foregoing sexual intercourse. 

Environmental determinism is the theory that the environment determines, plays a decisive role, or causes social and cultural development. "A region's culture can be affected" is not as strong a characterization as a theory of determinism requires, and is in fact the theory of environmental possibilism. "Regional sociocultural development will affect local environmental conditions" gets the theory backwards, suggesting that culture determines the environment, while environmental determinism is a theory of cultural development, not economic development.

This is the definition of relocation diffusion. Stimulus, contagious, and hierarchical diffusion are all kinds of expansion diffusion. Expansion diffusion is when innovations spread to new places while staying strong in their original locations. For example, Islam has spread throughout the world, yet stayed strong in the Middle East, where it was founded.

A “modern cultural hearth” is defined as a global center of culture and economics with a worldwide influence (i.e. Tokyo, Paris, London, New York City, and Los Angeles). Despite its large population, Mexico City’s culture and economic exports do not match those of cities described as modern cultural hearths. Generally, a modern cultural hearth is a highly populated city in an extremely wealthy and culturally influential country (i.e. the United States, Japan, and China).

A “cultural hearth” is a place of origin for a widespread cultural trend. For example modern “cultural hearths” include New York City, Los Angeles, and London because these cities produce a large amount of cultural exports that are influential throughout much of the modern world. Ancient cultural hearths include, Mesopotamia, the Nile River Valley, and the Wei-Huang River Valley.

All cities, particular large metropolises like New York City and Paris, exert a pull on the area around them. This influence is social, economic, and political. People are drawn to large cities because of the abundance of opportunity that comes with having so many people in such a relatively small space. The farthest reach of a city’s social and economic influence is known as its “breaking point.” For example, London’s breaking point is probably the north coast of France, after which the influence of Paris far exceeds the influence of London.

Ancient cultural hearths are places where civilization first sprang up during the agricultural revolution that took place roughly eight to ten thousand years ago. All of these are notable places where the agricultural revolution took place except the Mississippi River Valley, which was not settled in large numbers until much later.

While diffusion is the more general movement of ideas, notions, and innovations, it can be broken down in its more specific functions. Contagious diffusion requires direct person-to-person contact, not the influence of trends observed in this question. Expansion diffusion deals with a single population, and so is insufficient for this multi-city movement. Diffusion by relocation is a sequential process in which the ideas are transmitted by their carrier agents (such as immigrants) as they evacuate old areas and relocate to new ones. While more appropriate than the first two, relocation is not quite as accurate an answer as hierarchical: a form of diffusion in which an idea spreads by trickling down from larger to smaller adoption units. Fashion is not being carried by people as they leave the larger cities, but is rather observed and adopted by smaller cities that don't have the means or resources to generate such ideas on their own.