2. Las mutaciones: I) son fuente de variabilidad genética.
II) pueden contribuir a la evolución.
III) siempre alteran el fenotipo del organismo.
Es (son) correcta(s):
A) solo I.
B) solo II.
C) solo III. D) solo I y II.
E) I, II y III.

the index of refraction of the second medium is higher. i just took the test trust me !

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.