C2 should really come after C3 Welcome to BFSU: › Forums › Volume One › Learning Progression “C”: Physical Science, Engineering and Technogy › Lesson C-2. Sound, Vibrations, and Energy › C2 should really come after C3 This topic has 0 replies, 1 voice, and was last updated 8 years ago by happycl8. Viewing 0 reply threads Author Posts November 16, 2016 at 12:23 am #974 happycl8Participant I noticed C2 should come after C3 due to prerequisites. Author Posts Viewing 0 reply threads You must be logged in to reply to this topic.