Racism is discrimination and prejudice towards people based on their race or ethnicity. Racism can be present in social actions, practices, or political systems (e.g. apartheid) that support the expression of prejudice or aversion in discriminatory practices. The ideology underlying racist practices often assumes that humans can be subdivided into distinct groups that are different in their social behavior and innate capacities and that can be ranked as inferior or superior. Racist ideology can become manifest in many aspects of social life. Associated social actions may include nativism, xenophobia, otherness, segregation, hierarchical ranking, supremacism, and related social phenomena. While the concepts of race and ethnicity are considered to be separate in contemporary social science, the two terms have a long history of equivalence in popular usage and older social science literature. "Ethnicity" is often used in a sense close to one traditionally attributed to "race", the division of human groups based on qualities assumed to be essential or innate to the group (e.g. shared ancestry or shared behavior). Racism and racial discrimination are often used to describe discrimination on an ethnic or cultural basis, independent of whether these differences are described as racial. According to the United Nations's Convention on the Elimination of All Forms of Racial Discrimination, there is no distinction between the terms "racial" and "ethnic" discrimination. It further concludes that superiority based on racial differentiation is scientifically false, morally condemnable, socially unjust, and dangerous. The convention also declared that there is no justification for racial discrimination, anywhere, in theory or in practice. Racism is sometimes described as a modern phenomenon, with it arising in the European age of imperialism, the subsequent growth of capitalism, and especially the Atlantic slave trade, of which it was a major driving force.