Answer: The correct answer is nucleotide.
Explanation:
Nucleic acids are the polymer of nucleotides which are attached with each other with the help of phospho-diester bonds.
Nucleotide consists of sugar (ribose in RNA and deoxyribose in DNA), phosphate group, and nitrogenous base (A, T, G, and in DNA; and A, U, G, and C in RNA).
Metaphase 1 is when <span>tetrads of homologous pairs lined up along the center of the cell and attached to the spindle fibers in meiosis. Hope I helped!</span>
Answer:
A.All involve the active transport of gases across membrane
I think it is the 3rd one because health problems at older age.