Alleles are two different forms of a single gene.
the basic unit of life is the cell
Answer:
In double-stranded DNA, the molecular double-helix shape is formed by two linear sugar-phosphate backbones that run opposite each other and twist together in a helical shape. The sugar-phosphate backbone is negatively charged and hydrophilic, which allows the DNA backbone to form bonds with water.
C is not an example of evolution so that is your answer
C is found in cell membranes