Breathing and Gas Exchange
Every breath you take feeds your cells the oxygen they need and clears out the carbon dioxide they produce. The respiratory system handles this exchange, and it works hand in hand with the blood. Understanding how air moves and where gases actually swap is a common and answerable test topic. This lesson explains breathing and […]
Heart, Blood, and Blood Vessels
Your heart beats about 100,000 times a day, pushing blood through a network of vessels long enough to wrap around the Earth more than twice. The circulatory system delivers oxygen and nutrients to every cell and carries away waste. Knowing its main parts and how blood flows is a reliable source of test questions. This […]
