How does the effect of a force differ when it is applied on (a) a rigid body, (b) a non- rigid body?

(i) When a force is applied to a rigid object, it does not change the interspacing of constituent molecules and does not change dimensions and can cause motion in it.
(ii) When a force is applied on a non-rigid object, it will change the interspacing between its constituent particle and cause a change in its dimensions and can produce motion in it.