Question

give an experiment which strongly opposed the inheritance of acquired traits

Answer 1

Cut off a mouse's tail.

After this mouse reproduce, cut that mouse's tail too.

Continue this process for as many generations as you want.

But it can be seen that, even after cutting the tail of mice for many generations, no tail-less mice can be seen.

This shows that acquired traits cannot be inherited.

Answer 2

Experiments were conducted where the tails of rats of 21 generations were cut. However, the rats in the subsequent generations were not born without a tail.

This suggests that traits that are acquired during the lifetime of an organism are not passed on to the next generations.

These changes are made in the somatic cells of the body and not the germinal cells. Thus, they are not inherited or passed on.  

Also, acquired traits do not direct evolution.