Answer to Question 1
The ancient Greek philosophers believed that human societies inevitably arose, flourished, and declined. They saw the past as better than the degraded present. The theologians and philosophers of medieval Europe and the Islamic world believed that human misery was inevitable and that there was little mortals could do to change things. They tended to believe that social conditions were the result of Divine Providence.
Answer to Question 2
Segregation is the ecological and institutional separation of races or ethnic groups. Segregation may be de jure, that is, supported by laws, or it may be de facto, that is, enforced by unwritten norms that have virtually the same effect as the laws--involuntary separation.
Life cycle of Obelia, a colonial cnidarian.
How long does it take for 90% of a sample of strontium-90 (half-life of 28.8 years) to decay?
Enduring Social Issues
Bandura's social-cognitive model of human behaviour
Survivorship curves for people in the United States in the early 20th and early 21st centuries
Generalized life cycle for land plants