Let's use process of elimination to answer this question!
D is wrong, and we know this because of the names of DNA and RNA. The D in DNA stands for deoxyribose, and the R in RNA stands for ribose. These are the types of sugars in each nucleic acid. Therefore, they don't both contain a ribose sugar.
C is wrong, and this is because RNA does not contain thymine, but uracil instead.
B is wrong, and we know this because we know that RNA is composed of only one strand, and therefore it is not composed of multiple stands (plural).
Therefore, A must be right. We can confirm this, because we know that polymers are large molecules consisting of repeated subunits. DNA and RNA are both polymers consisting of nucleotides.<span />
The separation of the sister chromatids during the cell division occurs in the anaphase in mitosis and anaphase II in meiosis.
During the anaphase in mitosis, and the anaphase II of the meiosis, the chromosomes aligned at the center of the nucleus separates and the sister chromatids of the chromosomes starts moving towards the opposite poles as the spindle fibers starts contracting.
