Which term refers to the amount of random turning in response to the intensity of a stimulus?

The correct term that refers to the amount of random turning in response to the intensity of a stimulus is klinokinesis. This phenomenon specifically describes how an organism changes its rate of turning as a reaction to the strength of a stimulus, such as light or moisture. An increase in stimulus intensity leads to more frequent and more pronounced turning, allowing the organism to adjust its movement in response to its environment.

In contrast, kinesis generally refers to a non-directional movement that occurs in response to a stimulus, focusing more on the overall movement rate rather than directional turning. Orthokinesis describes changes in the speed of movement rather than turning patterns. Vernalisation, on the other hand, involves the process by which plants require exposure to a period of cold temperatures to induce flowering, which is distinct from movement responses.