Final answer:
The statement is true (option A); the atria have thinner walls because they transfer blood to the ventricles without needing the high pressure that the ventricles require to pump blood throughout the body.
Step-by-step explanation:
The statement that 'atria walls are thinner because they do not experience the large pressure that the ventricles experience during contraction' is true. The atria's primary function is to receive venous blood and transfer it to the ventricles, which they do with less force than is required for ventricular contraction. The ventricles, particularly the left ventricle, need to generate high pressure to pump blood throughout the systemic circuit, necessitating a thicker myocardium. The ventricular muscle thickness differs significantly, with the left ventricle being noticeably thicker than the right ventricle to accommodate the increased pressure and resistance it faces in the systemic circulation.