All types of cells can replicate at random. a.) true b.) false

No, all cells do not replicate in a random fashion, and hence the statement is false.

Option B

Explanation:

Each cell follows a specific cycle called the cell cycle and it follows that, these cell cycle has different phases such as the G0, G1, G2 and the M phase.

Only at the M phase the cell divides. At the G0 phase the cell rests and does not duplicate. In addition there are check points in between the phases of cell cycle that ensures the duplication in an orderly fashion.

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.