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.