Which of the following can cause scientific knowledge to change?

a. negative public opinion against existing knowledge

b. a change in observations that challenge existing knowledge

c. a change in government regulations that makes existing knowledge inconvenient

d. media reports that contradict existing knowledge

Define the apical impulse and describe its normal location, size, and duration. which abnormal conditions may affect the location of the apical impulse? explain the mechanism producing normal first and second heart sounds. describe the effect of respiration on the heart sounds. describe the characteristics of the first heart sound and its intensity at the apex of the heart and at the base. describe the characteristics of the second heart sound and its intensity at the apex of the heart and at the base.