Hugo de Vries worked on which of the following organisms?

Which of the following is most difficult to detect?

When different genotypes exhibit the same phenotype due to environmental differences,each is known as a .........

$A$ mutation that arises due to a change in a single base pair of $DNA$ is known as .... mutation.

$...$ is a phenomenon by which genetic variation is achieved through changes in the base sequences within genes,which creates a new character or trait absent in the parental generation.

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