Suppose a researcher is performing an experiment on children. She tests the children on one level of the independent variable at the beginning of the school year, but cannot return to test the second level until mid-April, when the school year is almost completed. What threat to internal validity may be a problem

The answer is "Maturation".

Explanation:

When we develop and evolve, we go thru a process called maturity. There are many different types of maturity, including physical and cognitive. As people age, our bodies expand and change, and it is called physical maturity. Cerebral maturity is the mechanism by which our sufficient detail increases as people mature. The educators should share, discuss, and agree upon their goals for student accomplishment and advancement.

so, colonists did not want to pay any taxes.  

colonists did not consider themselves british citizens.  

colonists felt no sense of obligation to britain.  

colonists objected to violations of their natural rights. are the answer choices?

answer; the parasympathetic nervous system;