A___ change occurs when a substance changes phase.

Match term definition ellipse a) diagonal cross section of a cylinder circle b) diagonal cross section through the widest part of a sphere sphere c) cross section parallel to the base of a cone great circle d) shape created when a semi-circle is rotated around the y-axis triangle e) perpendicular cross section of a cone

Which characteristics can be used to differentiate star systems? check all that apply.

In a ball-and-stick molecular model, what do the sticks represent?