Analyzing Assertion (A): Arteries Have Thick and Elastic Walls

The Assertion (A) states that arteries possess thicker and more elastic walls when compared to veins. Let's examine this:

• Arteries: These blood vessels carry oxygenated blood (except for the pulmonary artery) away from the heart to the rest of the body. The heart pumps blood into arteries at high pressure. To withstand this pressure and maintain blood flow, arteries need strong, muscular, and elastic walls. The elasticity allows them to stretch when the heart beats and recoil between beats, helping to regulate blood pressure.
• Veins: These vessels carry deoxygenated blood (except for the pulmonary vein) back towards the heart. The blood pressure within veins is significantly lower than in arteries. Consequently, their walls are generally thinner, less muscular, and less elastic than those of arteries.

Based on their functions and the pressures they handle, Assertion (A) is true. Arteries indeed have thicker and more elastic walls than veins.

Analyzing Reason (R): Arterial Blood Pressure is Low

The Reason (R) claims that the blood pressure in arteries is low compared to veins. Let's analyze this:

• Arterial Blood Pressure: As mentioned, the ventricles of the heart contract forcefully to pump blood into the arteries. This results in high pressure within the arterial system. The highest pressure is recorded during ventricular contraction (systolic pressure), and the lowest is between beats (diastolic pressure).
• Venous Blood Pressure: By the time blood reaches the veins, much of the energy from the heart's pumping has dissipated. The pressure in veins is substantially lower than in arteries.

Therefore, the statement that blood pressure in arteries is low compared to veins is factually incorrect. Reason (R) is false.

Conclusion of the Analysis

Our analysis shows that Assertion (A) is true, describing the structural adaptation of arteries to high pressure. Reason (R) is false because arterial blood pressure is high, not low, compared to venous pressure.

Thus, the correct statement is that (A) is true and (R) is false.