Question

why are traits acquired during the lifetime of an individual not inherited??

Answer 1

Change in non-reproductive tissues, on account of acquired traits, cannot be passed on to the DNA of the germ cells. Therefore, experience gained ortraits acquired during the life-time of an individual not inherited

Answer 2

Why are traits acquired during the lifetime of an individual not inherited?

Acquired characters bring about changes in somatic cells or organ (somatoplasm).

Somatoplasm doesn't take part in reproduction as germplasm is responsible for the formation of gametes.

Unless a change occurs in germ cells, it cannot be inherited.