Which of the following is true about veins? 1. Veins have valves; arteries do not. 2. Veins carry blood away from the heart, while arteries carry blood to the heart.3. Veins are more muscular than arteries.4. Veins have a smaller diameter lumen than arteries.

Drag each label to the correct location. each label can be moved more than once match the properties with the subatomic particle

Select the correct answer from each drop-down menu. in an experiment, dr. travis examined the effects of calcium intake on osteoporosis, a condition that causes an increased risk of bone fractures. the amount of calcium is variable. the risk of bone fractures .

Describe the function of the endomembrane system? what organelles are involved?