Which term means the level of effort required to complete an activity?

Intensity is the term that denotes the level of effort required to complete an activity. It reflects how difficult an exercise is for a certain person to complete and the amount of oxygen the body uses to do an exercise and the amount of calories burned while doing the activity. The higher the intensity, the harder the activity, the higher the heart rate, and the more burned calories.

the aorta is the large artery leaving the heart branches into smaller arteries, which eventually branch into capillaries.the arteries carry oxygen and nutrients away from your heart, to your body's tissues. the capillaries are small, thin blood vessels that connect the arteries and the veins. the statement that arteries carry oxygen-rich blood to capillaries is true. veins on the other hand are blood vessels that take oxygen-poor blood back to the heart.