Concept:Double circulation is the blood flow pathway in humans with two separate circuits: pulmonary and systemic.
Explanation:In double circulation, the right side of the heart pumps deoxygenated blood to the lungs via the pulmonary circuit.
The lungs oxygenate the blood and remove carbon dioxide.
Oxygenated blood then returns from the lungs to the left side of the heart.
The left side of the heart pumps this oxygen-rich blood to the rest of the body via the systemic circuit.
Therefore, the statement that oxygenated blood reaches the left side of the heart from the lungs is true.
Option B is false because blood on the left side is oxygen-rich, not poor in oxygen.
Option C is false because deoxygenated blood from the right side (not left) goes to the lungs.
Option D is false because oxygenated blood from the left side (not right) is sent around the body.
Thus, only option A correctly describes double circulation.
Answer:Option A: Oxygenated blood reaches the left side of the heart from the lungs.
