In a market economy, workers face various constraints that limit their economic well-being. The most direct constraint is the income they receive for their labor, which is determined by supply and demand dynamics in the labor market. While firms also face constraints regarding resource prices and consumers face constraints regarding the prices of goods, the question specifically highlights the income limitation as a primary factor affecting the worker's ability to participate in the economy.

Mercantilism was an economic theory prevalent in Europe from the 16th to 18th centuries. It emphasized accumulating wealth through a positive balance of trade. Colonies were essential to this system because they provided cheap raw materials for the mother country's manufacturing sector and served as exclusive, captive markets for the finished goods produced by the imperial power, thereby preventing wealth from leaking to rival nations.

The cottage or putting-out system was a decentralized production method where merchants provided raw materials to workers who produced finished goods within their own homes. This system preceded the factory system and allowed families to supplement their income by working independently, representing a transition phase in industrial history.

The term 'property right' is used here in a broad legal sense to describe the exclusive authority an owner has over their intellectual creation. While 'Copyright' is the specific legal mechanism, the provided answer key identifies 'property right' as the intended choice. This reflects the concept that intellectual creations are intangible assets protected under legal frameworks to incentivize innovation and authorship.

Social sciences focus on human behavior, social structures, and economic systems. The interaction of drugs in the human body is a biological and pharmacological process, which falls under the domain of natural sciences like biology or medicine. While the social impact of drug use is a social science topic, the physiological interaction of chemicals within the body is not.

Economics is defined as the social science that examines how societies manage their limited resources. It focuses on the mechanisms and decision-making processes regarding what goods and services to produce, the methods of production, and the distribution of these outputs among the population to address the problem of scarcity.

Group marriage, defined as a union involving multiple men and multiple women, has been documented in anthropological studies but is not a widespread or enduring social institution. Most societies favor monogamous or polygamous structures. The rarity of group marriage suggests that it does not provide the same level of economic or social stability required for the long-term functioning of most human societies.

The tertiary sector, or service sector, dominates the U.S. labor market. It includes industries such as healthcare, finance, education, and hospitality. As economies develop, there is a structural shift away from agriculture (primary) and manufacturing (secondary) toward services, driven by rising incomes, technological progress, and changing consumer preferences for intangible goods and specialized professional services.

Direct investment, such as establishing a wholly-owned subsidiary or building manufacturing facilities abroad, requires the greatest commitment of capital, management resources, and risk. Unlike exporting or licensing, it involves full ownership and control over operations within the foreign country, representing the deepest level of market integration.

Gordon Allport's theory suggests that prejudice often arises from economic competition. When groups compete for limited resources, jobs, or status, it fosters intergroup hostility and discriminatory attitudes. This economic perspective explains how perceived threats to one's livelihood or social standing can manifest as prejudice against 'out-groups' who are viewed as competitors in the economic sphere.