Why is a characteristic gained during an organism's lifetime not passed on to its offspring?
Because such characteristics are not useful enough to be worth passing on
Because the alleles carried in the organism's gametes are not changed by it✓Bonne réponse
Because offspring are formed before the characteristic can appear
Because only characteristics shown by both parents can be inherited
Explication
What an offspring receives is a set of alleles from the gametes of its parents, and a change to a parent's skin, muscle or memory does not rewrite those alleles. Saying such characteristics are too unimportant to hand on misses the point, since usefulness plays no part in deciding what a gamete carries.