Which special segment cuts through a midpoint at a 90 degree angle?
A) Median
B) Angle Bisector
C) Perpendicular Bisector
D) Altitude

A physical change is defined as "a usually reversible change in the physical properties of a substance,as size or shape" so its basically a change of a substance that you can see. You know a physical change has occurred if a substance has changed size or shape or in a way that you can physically see.