Why is the development of seeds considered to be important for the evolution of land plants from spore-bearing vascular plants? . . seeds in the formation of a well-developed root system.. . seeds in producing dominant sporophyte.. . seeds served as new means of dispersal for reproduction in areas without water..

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.