(i) mass of a body is always constant. Why ?
(ii) mass of a body can never be zero. Why ?
(iii) At the center of earth, weight of a body is zero. Why ?

Explanation

(i)Mass of body =quantity of matter in the body, which is constant.
(ii)quantity of matter in the body is fixed. It can not be reduced to zero.
(iii)`W=mg`, At the centre of earth, `g=0`, therefore, `W=0`.