I know terpeniods and terpenes play a role. Smell and taste are intimately related. amount of fertilizer present in flower tissues play a role as well. flushed or long cured buds will rid most of this buildup. If its not cured and fast dried you get a chlorophyl/grassy taste and a sweet tater tot smell lol.
thc is just one compound in the resin that coats the flowers/bud. the answer to that is neither. It is far more complex than that but the main source of the smell/taste is derived from the resin. Someone with a more in depth answer might be able to tell you the details.
