Which statement below does not pertain to nitrogenous bases Select one: a. form pairs by hydrogen bonding. b. guanine pairs with uracil. c. adenine pairs with thymine. d. cytosine and thymine are pyrimidines. e. allows variation from one nucleotide to another which creates the encoded information.

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.

digestion

it excretes wastes

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.