Identify the route of the oxygen transport in the body from earlier to later

Question

Accepted Answer

The correct option is (4):
The correct sequence traces the path of an oxygen molecule from the atmosphere into the body and through the circulatory system for delivery. First, inhaled air travels down the respiratory passage, which includes the **Trachea**. The air then reaches the deep lung tissue, specifically the **Alveole** (alveoli), where the vital gas exchange takes place. The oxygen diffuses from the alveoli into the blood vessels and is carried by the **Blood** (bound to hemoglobin). This oxygenated blood then returns to the left side of the **Heart**, which acts as the pump. Finally, the heart forcefully pushes this oxygen-rich blood into the **Artery** (starting with the aorta) for distribution to all organs and tissues in the systemic circulation.

The incorrect option is (1):
This option lists the sequence as Alveole, Trachea, Blood, Heart, Artery. The primary error is placing the **Alveole** before the **Trachea**. In reality, inhaled air must pass through the **Trachea** (the main windpipe) and the bronchial tree before it can reach the **Alveoli** for the gas exchange to occur. Therefore, the order of the first two steps is reversed from the actual path of air into the lungs.

The incorrect option is (2):
This sequence is Blood, Trachea, Alveole, Artery, Heart. This option begins incorrectly with **Blood**, suggesting the oxygen is already in the bloodstream at the start of its journey, which overlooks the essential steps of intake through the airways. Furthermore, the order of the circulatory components is wrong, as the oxygenated blood leaves the lungs and goes to the **Heart** (the pump) before it is distributed through the major blood vessels, the **Artery**.

The incorrect option is (3):
This sequence is Trachea, Alveole, Artery, Heart, Blood. While the initial respiratory steps (**Trachea, Alveole**) are correct, the circulatory path is flawed. After oxygenation in the alveoli, the blood flows to the **Heart** first to be pumped. It is only *after* leaving the heart's left ventricle that the blood enters the **Artery** (aorta) to begin its systemic journey. Thus, the order of Heart and Artery is incorrectly reversed in this option.