Which mrna sequences would form a structure that is a cue for transcription termination of some genes? 5 ′ − ggcccagggcc − 3 ′ a sequence of uracil–adenine rna–dna base pairs 5 ′ − ggcccagggcc − 3 ′ a palindromic gc‑rich region followed by a sequence of uracil residues in the rna a stem‑loop hairpin structure preceded by a sequence of uracil residues

The correct answer is "a palindromic GC‑rich region followed by a sequence of uracil residues in the RNA".

Explanation:

Hairpin loops are among the most common structures that mRNA could form that result in transcription termination. These structures are formed when a region of the mRNA base pairs with another region in the same strand, which often occurs in mRNAs with palindromic GC‑rich region followed by a sequence of uracil residues in the RNA. The GC-rich regions base pairs to each other and the sequence of uracil residues are the ones that form the head of the hairpin loop.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.