The precipitate that is most likely formed from a solution containing Ba+2, Li+, OH-1, and CO3^-2 is BaCO3.
This is because carbonates of all metals except sodium, Lithium potassium (group 1) and ammonium are insoluble in water. Hydroxides of sodium, Lithium, potassium and ammonium are very soluble in water, calcium and barium are moderately soluble. Ba(CO3) is insoluble in water and therefore forms a precipitate.
The best answer to this question is DNA. DNA holds the genetic makeup of the body in each individual cell. RNA is part of DNA. The nucleus holds the DNA. Ribosomes turn RNA into protein. That is why the answer cannot be RNA, ribosomes, or the nucleus.