Who proposed the Mutation Theory?

The concept of sudden genetic change in organisms,which results in true breeding in reproductive organisms,is known as:

$A$ mutant microorganism is unable to synthesize a component required for its growth,but it is able to grow if that component is provided. This is called a/an......

Hugo de Vries formulated the "Mutation Theory" based on the experiments he conducted on:

$A$ mutation in a single base pair of a gene results in the production of a non-functional protein. This type of mutation is called .............

Hugo de Vries proposed the Mutation theory by studying the plant called . . . . . . .