sentence2_structure: Compounds<>containing<>the element carbon$$$Compounds containing the element carbon<>are<>the basis of all known life
sentence1: For all compounds containing carbon, C is listed first, followed by H, if present, and them by remaining elements in alphabetical order.
sentence2: Compounds containing the element carbon are the basis of all known life.
question: Compounds containing which element are the basis of all known life?