Question

blood pressure is a measure of... how hard your heart has to work to pump your blood out through your veins. how hard your veins have to work to move blood back to your heart. how hard your heart has to work to pump your blood out through your arteries. how hard your arteries have to work to move blood back to your heart.

Explanation:

Blood pressure measures the force exerted by the heart to pump blood through arteries. Arteries carry oxygen - rich blood away from the heart. Veins carry blood back to the heart and are not related to the measurement of blood - pressure in this context.

Answer:

how hard your heart has to work to pump your blood out through your arteries.