Suppose some organisms ferment lactose but can't use citric acid for all their carbon needs. these organisms must be a) shigella. b) salmonella. c) escherichia. d) citrobacter.

The right answer is Escherichia coli

These four bacteria are from the family Enterobacteriaceae. They are bacillus gram negative bacteia.

E. coli ferments lactose and does not use citrate as a carbon source.

Shigella does not use both lactose and citrate.

Salmonella and citrobacter can use citrate as a carbon source.

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

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