Which is a characteristics of a physical change?
a. the chemical bonds i the substance are uncharged
b. the change cannot be seen
c. the molecules all move at the same speed
d. the substance has reacted with another substance

Physical Change characteristic is the chemical bonds in the substance are unchanged. Because a physical change is any change happens in an object but without involving a change in its chemical substance. Example, Solid to liquid change or also known as melting, liquid to gas change also known as evaporation, gas to solid change also known as deposition, liquid to solid or solidification, solid to gas or sublimation, and gas to liquid or condensation. The physical form of a substance is change into a new form but the chemical is unchanged.

B. convex since the words are bigger