Animal experimentation, also called animal testing, has contributed to many important scientific and medical discoveries; many people object to the use of animals in scientific studies because animals are denied their freedom and often suffer injury and discomfort; others identify certain practices as cruel while still recognizing the benefits.
The definition of bullying has expanded beyond traditional notions of a bigger, stronger child picking on a smaller, weaker victim. Bullying can occur in virtually any interpersonal setting. While it affects young people as well as adults, the issue is primarily considered in contexts involving school-aged children and adolescents.
Depression is a mood disorder that causes persistent feelings of sadness, hopelessness, and decreased energy. However, depression is more than just unhappiness. It can be severe enough to interfere with work, school, and other daily activities. Doctors also refer to this condition as major depressive disorder or clinical depression.
The term global warming first appeared in geochemist Wallace Broecker's 1975 Science magazine article, "Climatic Change: Are We on the Brink of a Pronounced Global Warming?" Scientists began studying the effect of greenhouse gases on Earth's climate more than a century prior, however, as early as 1820.