QUES: The physician holds a urine glass his own up against the candle Death sneaks up from behind places his left hand on the physicians shoulder and grabs the glass with his right hand

correct the punctuation.

CORRECTED: The physician holds a urine glass (his own?) up against the candle. Death sneaks up from behind, places his left hand on the physician's shoulder and grabs the glass with his right hand.

QUES: There meat and fat is replacing much of the traditional diet which is primarily composed of rice and beans

correct the punctuation.

CORRECTED: There, meat and fat is replacing much of the traditional diet, which is primarily composed of rice and beans.

QUES: where now q1 and q2 are the electrical charges and the dielectricity constant in vacuum

correct the punctuation.

CORRECTED:
where now q1 and q2 are the electrical charges, and the dielectricity constant in vacuum.