The threat of history refers to: a. that some subjects with ...

[casperchen82]

The threat of history refers to:
 
  a. that some subjects with have had history classes and others have not
  b. the realization that some subjects have learned from history while others have not
  c. events external to the experiment that will impact the results
  d. the fact that only current, relevant subjects need to be studied

Question 2

Essentially, an experiment examines the effect of:
 
  a. the world we live in
  b. modern science
  c. an independent variable on a dependent variable
  d. science on sociology

[verrinzo]

Answer to Question 1

c

Answer to Question 2

c