The precambrian time period is segmented into very few parts because: . a.. the fossil record is scarce. b.. life did not exist. c.. cyanobacteria were the only life form. d.. volcanic activity ruined the fossil record.

The answer is letter A. Fossil records are very scarce to find

The Precambrian era refers to the earliest era of the earth. During this time, there were less evidences of life was found. Though there were some rocks that originated from this era however scientist are not sure if it was in the Precambrian era

the answer for this question would be d. glaciers

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.