Choose if the response describes the “primary exposure” or “secondary exposure” to an antigen.  Assume these are normal immune responses. Memory cells are created for the first time. [ps1] A lag period of several days occurs before antigen-specific antibodies appear in the bloodstream. [ps2] IgM antibodies are formed early and later followed by IgG. [ps3] Even small amounts of antigen can trigger a response. [ps4]

To answer this question, type the sequence of numbers in the correct order. A T cell uses a CD4 receptor recognizes the antigen on the dendritic cell and forms a complex. The B cell responds to chemical mediators, differentiates, and secretes antibodies. The dendritic cell digests the antigen and displays it using the MHC marker. The CD4 cell differentiates into a T helper cell. A dendritic cell phagocytoses an invader and its antigen. A specific B cell clone processes the antigen, then complexes with the activated T helper cell.  

A boy is born to a family of peasant farmers who own their own small plot of land. Though no one owns the boy, due to the stratification system of his society, he has no social mobility, or no choice but to live as a peasant farmer until his death. The stratification system discussed here is a:

Which of the following scenarios best represents outsourcing?

Which of the following best describes the process of socialization?

When research questions have more to do with how people interact and less with how they say they interact, what research method is usually best?

The richest 20% of Americans take home about _______ of the country’s income each year.

In meeting our basic human needs:

Qualitative research relies on __________.

In comparison with other countries with advanced economies, the United States has _________.