People who participate in an experiment, whose reactions or responses are observed as part of the experiment, usually to test the validity of a hypothesis, are called

speed

explanation:

stewards ice box was the purchase of alaska from russia and it was called that because people thought it was not a good idea to purchase alaska

swahili is an extremely rich and complex civilization, a set of ethnic groups articulated by a language and a series of cultural elements that fuse the african traditions, islam and indian culture. this growth was largely a result of the indian ocean trading network that brought in not just man-made riches, but also religious ideas, specifically islam, which had a significant impact on the local culture. furthermore, the development of the swahili language gave a common cultural unity to the people.