The image above shows particles in a medium. which of the following show the worst conditions for a sound wave to travel in. i don't have the picture but picture a had particles together evenly. picture b has particles clumped together. c has particles loose. then d has no particles

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.