Mixture would be the piece of pure gold. I don't know the explanation but the answer is mixture, I'm sure about that it is mixture, I read it somewhere.
Well, for one thing, they ensure that a scientist can't claim a certain result, which might be biased and thus inaccurate, because he or she is being paid by, say, big business interests. For another, they ensure that medicines or treatments can't be made available to the public without thorough testing, replication, and peer review.
63/29 Cu (copper-63)
65/29 Cu (copper-65)
24/12 Mg (magnesium 24)
25/12 Mg (magnesium 25)
26/12 Mg (magnesium 26)
6/3 Li (lithium 6)
7/3 Li (lithium 7)
The top number is the mass number and you find that by adding the number of neutrons and atomic number
The bottom number is the atomic number and it’s the number or protons
northern america is the correct answer i’m pretty sure