According to Hugo de Vries,the mechanism of evolution is

Organisms that possess favorable variations are considered to be:

Organic evolution would not have taken place:

Hugo de Vries's experimental organism was

Assertion : Natural selection is the outcome of difference in survival and reproduction among individuals that show variation in one or more traits.
Reason : Adaptive forms of a given trait tend to become more common; less adaptive ones become less common or disappear.

Who proposed the mutation theory of evolution? Explain it.