Step-by-step explanation:
Q1:The doctor is testing the patellar reflex of the knee.
Q2:This test usually examines the knee .
Q3:An abnormal result might be an exaggerated reflex or a poor one these can show neurological damage so it is important that it is treated early on.
Q4:The muscles are weak if the patient is an oldie but as a kid muscles are pretty strong so reflexes will be better.