Acontrolled experiment is one that tests experimental and control groups in parallel
true/false

True                                                                                  

Explanation:

Controlled experiment: In psychological research, a controlled experiment is referred to as scientific research or test that is being directly manipulated through the researcher, scientists, or experimenter to measure a particular variable at a time. In a controlled experiment, the variable that is being tested or measured is an independent variable and therefore it is being adjusted to know its effects on the specific system which is being studied.

In the question above, the given statement is true.

sumerians were polytheistic, meaning they believed in many different gods. so, the best answer is c.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )