How do the genes in E. coli save energy?

Genes are turned on periodically.

Genes are never turned on.

Genes are turned on only when needed.

Genes are turned on all of the time.

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How does a gymnosperm prevent itself from pollinating the same tree

Match each medication with its description.

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit.there is a precise compatibility between the active site and the lactose molecule.specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed.reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.