Exhibits Drag from Word Choices to complete the sentence. Heart sounds are loudest for S1 at the dropdown. And for S2 at the dropdown

Rationale: • Center of the heart: The center of the heart is not an anatomical landmark used to differentiate heart sounds. Heart sounds are best heard at specific points related to valve locations, and the "center" does not correspond to where S1 or S2 are loudest. • Apex of the heart: The apex of the heart is located at the fifth intercostal space at the midclavicular line. S1, produced by the closure of the mitral and tricuspid valves, is loudest here because these valves are closest to the apex region. • Right side of the heart: The right side of the heart involves the tricuspid and pulmonary valves, but it is not a location used for distinguishing where heart sounds are loudest. Both left and right-sided valves contribute to S1 and S2, but loudness is associated with specific auscultation sites, not broadly the right side. • Base of the heart: The base of the heart is located at the level of the second intercostal space near the sternum. S2, produced by the closure of the aortic and pulmonic valves, is loudest at the base because these semilunar valves are positioned superiorly. • Left side of the heart: The left side of the heart includes the mitral and aortic valves but saying simply "left side" does not accurately describe where S1 or S2 are best heard. The terms apex and base are used instead because they specifically relate to the loudest points for heart sounds.