Which sentence is an example of how a scientist might use a model? A. A wrench is used to tighten a nut onto a piece of wood.

B. A microscope is used to magnify a group of cells on a slide.

C. A stopwatch is used to time the rate of a chemical reaction.

D. The end of a slinky is moved vertically up and down to simulate a wave.

Iwould appreciate if someone could me.

Achemist at a pharmaceutical company is measuring equilibrium constants for reactions in which drug candidate molecules bind to a protein involved in cancer. the drug molecules bind the protein in a 1: 1 ratio to form a drug-protein complex. the protein concentration in aqueous solution at 25 ˚c is 1.74 x10-6 m . drug a is introduced into the protein solution at an initial concentration of 2.00 x10-6m. drug b is introduced into a separate, identical protein solution at an initial concentration of 2.00 x10-6m. at equilibrium, the drug a-protein solution has an a-protein complex concentration of 1.00 x10-6m, and the drug b solution has a b-protein complex concentration of 1.40 x10-6m. a. calculate the kc value for the a-protein binding reaction. b. calculate the kc value for the b-protein binding reaction. c. assuming that the drug that binds more strongly will be more effective, which drug is the better choice for further research?

Avogradoa number was calculated by determining the number of atoms in?