Which ecological level consists of all the ecosystems found on earth?

a) organism

b) population

c) biosphere

d) community

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.

Produce proteins by following coded instructions that come from the nucleus of the cell.

Select the word from the list that best fits the definition apparent movement of a star used to measure its distance from earth