Eugenia is participating in a social-psychological research experiment, and the researcher, Emilio, reads the instructions to her and the other participants so that everyone in the study hears exactly the same instructions. By standardizing the instructions, Emilio is attempting to control the

changes in factors like average income and preferences can cause an entire demand curve to shift right or left. this causes a higher or lower quantity to be demanded at a given price. demand curves relate the prices and quantities demanded assuming no other factors change. it is important for consumers to know this information, because it is crucial for them to know what they can afford and can't afford. i hope this .

answer; people have no objective standard by which to judge themselves;

answer; coal reserves in the u.s are far greater than petroleum reserves;