AP PSYCHOLOGY

Detailed explanation-1: -In general, a stimulus is something that provokes or causes an action or response, as in Failing that test was the stimulus I needed to start studying harder. The plural of stimulus is stimuli. Its verb form is stimulate, which typically means to spur into action or to invigorate.

Detailed explanation-2: -The ability of an organism to respond to external stimuli is called sensitivity. For example, Plants grow towards light(external stimuli) sources, and if the direction of light is changed, the plant will also change its direction of growth to accommodate for survival. So, the correct answer is ‘Sensitivity’.

Detailed explanation-3: -When a stimulus is detected by a sensory receptor, it can elicit a reflex via stimulus transduction. An internal stimulus is often the first component of a homeostatic control system. External stimuli are capable of producing systemic responses throughout the body, as in the fight-or-flight response.

Detailed explanation-4: -excited by three types of stimuli-mechanical, thermal, and chemical; some endings respond primarily to one type of stimulation, whereas other endings can detect all types.