Blood Pressure Gradient in Circulatory System Steps:

• Order vessels as aorta, large arteries, arterioles, capillaries, venules, veins.
• Assign relative pressures: +++ for highest (aorta/large arteries, ~100 mmHg), ++ for medium (arterioles/venules, ~40-10 mmHg), + for lowest (capillaries/veins, ~25-2 mmHg).
• Match sequence to decreasing gradient due to frictional losses and resistance.
• Verify highest pressure location aligns with ventricular output.

Why A is correct:

• A matches the pressure drop from high in aorta/arteries (+++/++) to low in capillaries/veins (+), per Poiseuille's law where pressure decreases with increasing resistance downstream.

Why the others are wrong:

• B: Equal pressures across parts (+ + +), ignores resistance-driven drop.
• C: Incorrectly labels veins/capillaries as lowest without proper high-to-low sequence.
• D: Reversed pattern starts high in veins, contradicting arterial-to-venous gradient.

Final answer: A