All Electromagnetic Waves travel at 3.0 x 108 m/s in a vacuum or air
The answers below lists the Speed of light in four different situations.
A: 3.0 x 108
B: 2.2 x 108
C: 1.9 x 108
D: 1.7 x 108

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.