The word or phrase to fill into the gap is the "Ku Klux Klan", an extreme right organization calling for what they would call a "purification" of the US-American society.
Cans,bottles,plastic, and paper
Brackish water is water that has some salt/sea water, but is mostly fresh.
There is one word to describe the culture in the Middle Ages and that is barbaric. While some countries were better than others at maintaining order and the education of their society it was quite a rough time to exist when people had little to no rights.
The answer to this question is <span> fixed ratio
In a </span> fixed ratio schedule of reinforcement, it requires <span>subjects to provides a set number of responses and a reward will be given after the completion of a certain numbers. Because of the high certainty, we will tend to receive high and steady rate of response if we use this type of schedule.</span>