human
Question: Sulfur (S), oxygen (O2), water (H2O), and sodium chloride (NaCl) are all examples of pure substances. Which of the following describes all pure substances?

Choices:
A) A pure substance consists of only one type of element.
B) A pure substance has a definite chemical composition.
C) A pure substance cannot be broken down into simpler substances.
D) A pure substance is normally found as a solid at room temperature.
gpt
The correct answer is 1: A pure substance has a definite chemical composition..