The one factor in an experiment that changes is what

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

The items in the following list are all units of matter. which is the smallest unit that retains the properties of the matter? a.) atom b.) compound c.) electron d.) element

Which is a substance that can be separated by physical means and is not the same throughout