Question

multiple-choice question
water and copper are considered a pure substance because...
they are made of the same substance
they are made of multiple substances

Explanation:

A pure substance is made of only one type of particle (either an element like copper or a compound like water). The first option states they are made of the same substance (consistent with pure substance definition), while the second option says multiple substances (which is a mixture, not pure substance).

Answer:

A. they are made of the same substance