(20 POINTS) Which statement BEST explains how RNA polymerase knows where to start & stop making an RNA copy of DNA? -The enzyme proofreads each DNA strand to help ensure each molecule is copied exactly in the order of the original strand

-The enzyme binds to a sequence of nucleotides called introns they are cut out before they become functional

-The enzyme splices exons together before transcription begins to form the final mRNA molecule

-The enzyme only binds to regions of DNA known as promoters, which have specific base sequences

The enzyme only binds to regions of DNA known as promoters, which have specific base sequences

the answer to your question is b

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.