Final answer:
The Heimlich maneuver is performed on an adult when they are choking and unable to speak or breathe.
Step-by-step explanation:
The situation that would call for the Heimlich maneuver to be performed on an adult is when the person is choking and unable to speak or breathe. This could include scenarios where the person is bending over and coughing but not talking, unconscious on the ground and unable to talk, or gasping for air but not coughing or talking. In these situations, performing the Heimlich maneuver can help dislodge the blockage and restore the person's ability to breathe.
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