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.