AP BIOLOGY

Detailed explanation-1: -The correct option is A. Stimulus. Any change in the environment to which an organism responds is called stimulus. The stimuli initiates an appropriate electrical impulse in the sensory neurons which transmits it to the brain or spinal cord.

Detailed explanation-2: -A change in an organism’s surroundings that causes the organism to react is called a stimulus (plural stimuli). An organism reacts to a stimulus with a response-an action or change in behavior. Another example is if you are cold, you shiver. The cold is the stimulus while the shivering is the response.

Detailed explanation-3: -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.

Detailed explanation-4: -Response : Response are any type of behavior of a living organism that results from a stimulus. Hence, the change in an organism resulting due to a stimulus is called response or reaction.

Detailed explanation-5: -response to stimulus Gene Ontology Term (GO:0050896) Definition: Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus.