Sally found that neither caffeine nor extraversion individually predicted problem solving; however, she found that they both worked together to predict problem solving. This is an example of what kind of an effect?
A) a true interaction
B) a suppressor
C) an evocation
D) a true mediation

A) a true interaction

Explanation: Problem solving includes using generic methods in an orderly manner to find solutions to problems. Some of the problem-solving techniques developed and used in philosophy, artificial intelligence, computer science, engineering, mathematics, or medicine are related to mental problem-solving techniques studied in psychology. To solve a problem one need to have an insight about the problem. Know what the problem is and then decide in the best approach to solve the problem.

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.

answer; differentiation;