The process of changing a higher form to a lower form is called a. claudication. b. contracture. c. crepitation. d. degeneration.

D. degeneration.

Explanation:

The term degeneration refers to the notion that species can return to a primitive state over time - a process that would be opposed to biological evolution. That is, according to degeneration a species may move out of its higher form and back into a lower, less evolved form.

In short, degeneration occurs when through the loss of characteristics that allow an organism to evolve evolutionarily, it loses beneficial qualities, such as strength and intelligence, and returns to a primitive state.