A involves random assignment of participants and manipulation of the causal variable, while a may have manipulation of the causal variable, but never involves random assignment of participants

true experiment, non-experiment

Explanation: A true experiment is the type of experiment carried out in which a conscious effort is made to control all the other variables in the experiment except the one variable under study/observation. This is often referred to as the most accurate form of research as it can be used to prove or disprove a hypothesis, given that all other variables are constant but one.

A non experiment on the other hand is a type of experiment where there's no room for control over or manipulation of the predictor variable, which means the researcher has to make inferences and conclusions from observations and interpretations. Such experiments are never conclusive enough to prove or disprove hypotheses.

his wha5

the historians cited in the article all agree with one another about the cause of the civil war. despite coming from different backgrounds and cultures, the historians agree that slavery was the root cause of the civil war. the fact that all these historiansgenerally agree with one another makes their shared viewpoints more reliable and valid, especially because the historians have different backgrounds and all work for the well-respected institutions of howard university, clemson university, and the university of colorado.