Most of what we know about the lac operon of E. coli has come from genetic analysis of various mutants. In the following list are the genotypes of six strains of E. coli. For each strain, indicate whether the lacZ gene product (B-gal) will be expressed in the presence of lactose and whether it will be expressed in the absence of lactose. Explain your reasoning in each case. (A "plus" superscript indicates normal functioning part of operon or repressor gene, a "minus" indicates loss of function, the P region is where the RNA polymerase binds, "Oc" means "operator-constitutive" mutant which means that the operator is mutated such that the repressor can’t bind, and "Is" means "super-repressor" which binds the operator, but doesn’t bind lactose (so never dissociates from the operator).

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.

i think that it is c, d, and e, hope this