In E. coli, a cluster of three genes called the lac produce enzymes that break apart lactose. To the side of the genes is a region called the , where RNA polymerase binds, and another region called the , where the lac repressor binds.

layer 3 is younger than layer 6.

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.

d. planting trees

the trees take in carbon to make oxygen.