In a line of students jenna is number 8 the teacher says that a rule for a number pattern is add 4 the first student in the line says the first term seven what number should jenna say a is 31 b is 35. c is 39

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.