Support - as Parker pointed out: the bonds that define alkanes, alkenes, and alkynes are between specifically carbons; for uniformity, I looked into the sister notes for “alkanes” and “alkynes.” The note for alkanes (nid 1555364466844) specifies that its single bonds are between carbons. I submitted & merged a suggestion for the alkynes note (nid 1555365292555) for this to also be specified