Question

Assertion (A): In complete transposition of the great arteries, compatibility with life requires that communication exists between the pulmonary and systemic circulation.

Reason (R): In complete transposition of great arteries, the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle.

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

Picture two separate loops running side by side; only a shunt lets oxygenated blood cross over.

Answer 1

The Correct Option is A

Step 1: Picture the normal circulation first.
Normally blood flows in a single loop, right side of the heart to lungs to left side of the heart to body and back again, so oxygen picked up in the lungs always reaches the body.

Step 2: Picture what transposition does to that loop.
In complete transposition, the aorta sits on the right ventricle and the pulmonary artery sits on the left ventricle, the opposite of normal. This splits the single loop into two closed loops running in parallel, one just cycling deoxygenated blood between the body and the right heart, the other just cycling oxygenated blood between the lungs and the left heart.

Step 3: See why survival needs a connection.
With two sealed parallel loops, oxygenated blood never crosses into the body's loop unless there is a shunt joining the two, through a patent ductus, a hole in the atrial wall, or a hole in the ventricular wall. So the Assertion, that life needs such a communication, is true, and it is true precisely because of the vessel arrangement given in the Reason.

Step 4: Confirm the Reason and drop other codes.
The Reason's description of the swapped great vessels is the accepted anatomical definition of this defect, so it stands as true and as the actual cause of the Assertion. This removes the code where R does not explain A, and it removes the codes that mark either statement false.

Final Answer:
Both statements are true, and the Reason is the correct explanation of the Assertion, based on standard physiology since the printed key was unreadable.