The theory proposed by Hugo de Vries is called .......

Which one of the following is $INCORRECT$ with respect to genetic drift?

The correct meaning of natural selection is

According to Hugo de Vries,the mechanism of evolution is

Present the views regarding the origin of variation and speciation.

$A$ scientist who worked on rats cut their tails up to $21$ successive generations,but at last,he found that the tails remained normal. Which scientist's theory is disapproved by this experiment?