A child has built a large block structure in his Head Start center. He now places two blocks upright and tries to make a bridge across them using a third block. He selects a block of the wrong length to make the bridge, however, and his structure topples. He tries again and again with this block, always getting the same result. A teacher moves over to him and says, "What if you tried a different block? Which block would be the right length?" The child thinks about this question, selects a longer block, and successfully completes the bridge. This is a good example of a teacher intervening:

A92-year-old man with a 45-year history of chronic obstructive pulmonary disease is intubated in the icu because of a bout of viral pneumonia that fails to improve after 72 hours of antibiotics. although the inspired fraction of oxygen is 100%, the patient's po2 remains at 57 mmhg. positive-end expiratory pressure (peep) is added to allow the inspired fraction of oxygen. twelve hours after the introduction of peep the patient suddenly become hypotensive. at the same time, his oxygen saturation drops from 92% to 61%. on physical examination, his bp is 80/50 mmhg and his pulse is 124/min. he has distended neck veins and distant heart sounds. which of the following would also most likely be seen on this patient's physical examination? - absence of breath sounds in the right hemithorax- high amplitude carotid artery upstroke- a pleural friction rub- pulsus alternans- splenomegaly