This threat to internal validity refers to changes in participants that occur over time during an

Dwaine has just completed a high school course in algebra. However, when he needs to solve a problem that uses basic algebra, he finds that he does not know how to apply his knowledge. Cognitive psychologists would argue that Dwaine

a. is having trouble because of the situated-cognition issue. b. should apply the matrix method, because it is especially useful for algebra problems. c. is probably using an inappropriate algorithm. d. should try parallel processing.

What is a major contributor to the increasing obesity rates in developing countries?

a. the adoption of Western foods b. eating foods low in sugar and fat c. the desire to look more "American" by gaining weight d. the sedentary lifestyles that most people in developing countries have