Which of the following is most likely to be an observation made by an anatomist?

A. RNA polymerase binds to a promoter, a DNA sequence that becomes a gene.

B. Sensory receptors convert information into impulses to be sent to the CNS.

C. The heart's epicardium forms a protective outer covering and secretes serous fluid.

D. The middle ear is an air-filled space that separates the outer and inner ear.