Here's how the sources can be categorized:
Unbiased Source:
- Research Subject: lowering the drinking age Source: A report from the National Transportation Safety Board
- Research Subject: advantages of a vegetarian diet Source: An expert on nutrition
Biased Source:
- Research Subject: the death penalty Source: An interview with an inmate on death row
- Research Subject: harmful effects of television Source: A study by Disney Channel
- Research Subject: use of animals in medical experiments Source: A speech by an animal-rights activist