21.   Cohart was an early investigator into the role that social factors play in chronic illness.

22.   Common environmental factors might also play a role.

23.   Clearly, those factors play a role.

24.   Even some economists who believe price manipulation was widespread say these other factors also played a significant role in the soaring prices.

25.   Energy companies have said cooler weather and other factors played a role.

26.   Everett Ehrlich, under secretary of commerce for economic affairs, defended the agency even as he acknowledged that special factors had played a significant role.

27.   Experts from countries with successful population control strategies all say social and political factors can play a major role.

28.   Environmental factors play large roles in newer histories of the West.

29.   Epidemiological studies have shown that eating disorders are more prevalent in industrialized countries, suggesting that cultural factors play a role in setting off the conditions.

30.   Genetic and hormonal factors play a role in hair loss.