When we breathe in, we inhale many gases, including oxygen. What happens to the gases that the body can't use?*1 pointThey circulate through the body and are disposed later.They are changed into oxygen by the lungs.They are absorbed into the digestive system and used to create energy.They are exhaled.

The human gas-exchanging organ, the lung, is located in the thorax, where its delicate tissues are protected by the bony and muscular thoracic cage. The lung provides the tissues of the human body with a continuous flow of oxygen and clears the blood of the gaseous waste product, carbon dioxide. Atmospheric air is pumped in and out regularly through a system of pipes, called conducting airways, which join the gas-exchange region with the outside of the body. The airways can be divided into upper and lower airway systems. The transition between the two systems is located where the pathways of the respiratory and digestive systems cross, just at the top of the larynx.T

1. How do the respiratory and circulatory systems work together in exchanging and transporting gases in our body?

Where, precisely, does oxygen from the air pass through the surface of the body so it can travel to the cells, and carbon dioxide pass out? Explain how this exchange takes place.

Ventilation includesMultiple Choiceinspiration only.expiration only.both inspiration and expiration.the volume of air that can be exhaled.the transportation of oxygen to cells in the body.

Recall what happens during gas exchange in the alveoli of the lungs. Carbon dioxide diffuses from air to bloodOxygen diffuses from air to bloodCarbon dioxide diffuses from blood to airOxygen diffuses from blood to air