Variation in genotype is caused by O None of the above
e phenotypes changing more quickly than genotypes.
o recombination of genes as a result of sexual reproduction.
O
O mutations only.

Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. Another source is gene flow, or the movement of genes between different groups of organisms. Finally, genetic variation can be a result of sexual reproduction, which leads to the creation of new combinations of genes.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.