Which sequence furthers scientific knowledge?
hypotheses generate a scientific question, leading to observations, which can be tested through an experiment
observations generate a scientific question, leading to a hypothesis, which can be tested through an experiment.
hypotheses generate a scientific experiment, leading to observations, which can be tested through a question
observations generate a scientific experiment, leading to a hypothesis, which can be tested through a question

i think that the best answer would be c.

tell me if im wrong : )

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.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).