Answer to Question 1
All groups set boundaries by distinguishing between insiders who are members and outsiders who are not. Sociologist William Graham Sumner coined the terms ingroup and outgroup to describe people's feelings toward members of their own and other groups. An ingroup is a group to which a person belongs and with which the person feels a sense of identity. An outgroup is a group to which a person does not belong and toward which the person may feel a sense of competitiveness or hostility. Distinguishing between our ingroups and our outgroups helps us establish our individual identity and self-worth. Likewise, groups are solidified by ingroup and outgroup distinctions; the presence of an enemy or hostile group binds members more closely together. Group boundaries may be formal, with clearly defined criteria for membership. Ingroup and outgroup distinctions may encourage social cohesion among members, but they may also promote classism, racism, sexism, and ageism.
Ingroup members typically view themselves positively and members of outgroups negatively. These feelings of group superiority, or ethnocentrism, are somewhat inevitable. Ingroups provide us not only with a source of identity but also with a point of reference.
A reference group is a group that strongly influences a person's behavior and social attitudes, regardless of whether that individual is an actual member. Reference groups help explain why our behavior and attitudes sometimes differ from those of our membership groups. For most of us, our reference group attachments change many times during our life course, especially when we acquire a new status in a formal organization.
Answer to Question 2
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Examples of cell types derived from ectoderm, mesoderm, and endoderm.
Examples of sterilizations and disinfection processes
Examples of thrombophlebitis. Deep venous thrombosis (DVT) commonly affects the veins of the leg.
The Physicians’ Desk Reference.
Examples of b-turns
Dietary Reference Intakes