A mixture IS a pure substance
(True or false)

no

Explanation:

Matter can be broken down into two categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. ... A chemical substance is composed of one type of atom or molecule. A mixture is composed of different types of atoms or molecules that are not chemically bonded.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.