Schoolgirl Liz Gets a Mouthful of Holiday Treats

So I've made it really simple for you, there's only three things to remember and each abbreviation

has three letters. So MSM and the MNMN. The NMN, not like M&M's, not like the candy, it's

NMN, nicotinamide monatide dinucleotide. So, remember MSM? **** methane. The clue

there is the S is sulfur, okay? The NMN, it's a bit tricky, bit of a mouthful, right? And

then R, remember this one? *****.