Match the Research Examples in 1-7 with the Main Threat

Multiple Choice

Match the research examples in 1-7 with the main threat to internal validity that it contains (a-g) .
-A researcher gives students a pretest on attitudes toward diversity and then implements his "teaching tolerance" curriculum to half of the classes. A month before the posttest, voters in the state pass a divisive anti-homosexual law.

A) Maturation
B) History or environmental events
C) Repeated testing
D) Instrumentation
E) Selection or assignment
F) Mortality or attrition
G) Statistical regression