Please choose the correct answer to the 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?

Answer1: A pure substance consists of only one type of element. Answer2: A pure substance has a definite chemical composition. Answer3: A pure substance cannot be broken down into simpler substances. Answer4: A pure substance is normally found as a solid at room temperature.

Answer format: answer1/answer2/answer3/answer4