Which of the following best describes the shape of a DNA molecule?
A. Two strands of nucleotides bonded together at their bases,
twisting to form a double helix
B. A single strand of nucleotides bonded together and twisted,
forming a sphere
C. A single strand of nucleotides bonded together, forming a long
chain
D. Two strands of nucleotides bonded together at their bases,
forming a flat ribbon