Which of the following is a sign of a physical change ? a) the formation of a new substance b) breaking apart one substance into two substances c) a change in the shape of a substance d) the rearrangement of particles in a substance

The correct answer option is C) A change in the shape of a substance.

Explanation:

Physical changes can be defined as the changes which affect the form of a chemical substance but not its chemical composition. These are the changes in which no bonds are broken or formed.

A change in the shape of a substance is a physical change because there is no change in composition of the substance chemically.

While all other options involve a change in chemical composition so they are not the examples of a physical change.

an electric circuit

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.