Answer:
Im not 100 percent sure but I think C because a chemical change occurs when the chemical has broken composure so I think its C.
Carbon and hydrogen.
The simplest group of organic molecules are the alkanes which have only these 2 elements. Eg methane, CH4.
Chargaff’s rules of base pairing gave Watson
and Crick confidence that their model was correct,
because their model agreed with Chargaff’s
observations of the relative percentages of A, T,
G, and C in DNA.
