Question

before we discuss how substances change, lets talk about how we identify them. substances have physical and chemical properties, or traits. you can use those traits to identify a substance. a substances physical properties include its shape, volume and freezing point. you can measure and observe these properties without changing the composition of a substance. for example, you can freeze liquid water to observe its freezing point without changing what the water is made of. the liquid water would become ice, but each molecule of water still contains two atoms of hydrogen and one of oxygen. a substances chemical properties include its ph level, flammability and reactivity with oxygen. you cant measure these properties unless you also change the way the atoms or molecules are arranged.

in the passage above, the \composition\ of a substance means

choose one option

a whether it is solid or liquid

b the atoms that make it up

c all of its physical properties

d how much water it can hold

Explanation:

The passage says "you can measure and observe these properties (physical properties) without changing the composition of a substance. For example, you can freeze liquid water to observe its freezing point without changing what the water is made of. The liquid water would become ice, but each molecule of water still contains two atoms of hydrogen and one of oxygen". So "composition" refers to what the substance is made of, i.e., the atoms that make it up.

Answer:

B. the atoms that make it up