Read the following statements regarding the mechanism of evolution:

I) According to Darwin evolution was gradual process.

II) de Vries believed single step large mutation caused speciation.

III) Lamarck said that evolution of life forms had occurred but driven by disuse of organs only.

The correct ones in the above are

Lamarck proposed theory of inheritance of acquired characters or the theory of use and disuse of organs. According to him, use of an organ leads to strengthening and development of that organ and disuse results in weakening of that organ. Lamarckism does not talk only about disuse of organs. Charles Darwin says evolution is a gradual process and Hugo de Vries believes in single step large mutations leading to speciation.