Question

in a physical change, a substances physical properties may change, but its chemical makeup does not. consider water, for example. water is made up of two hydrogen atoms and one oxygen atom. water is the only substance on earth that exists naturally in three states: solid, liquid, and gas. to change between these states, water must undergo physical changes. when water freezes, it becomes hard and less dense, but it is still chemically the same. there are the same number of water molecules present before and after the change. waters chemical properties remain constant. which phrase from the selection helps the reader understand the meaning of
emains constant\? change between only substance physical properties same number

Explanation:

The phrase "same number" indicates that something is not changing. In the context of water undergoing physical changes, the number of water molecules remains the same, which means its chemical properties remain constant.

Answer:

D. same number