Which term describes the response of a living organism to a stimulus?

Which term describes the response of a living organism to a stimulus?

• A. Metabolism
• B. Irritability
• C. Photosynthesis
• D. Homeostasis

Answer: (B)

Responding to environmental changes is called irritability. This captures how living things sense a stimulus and react to it, whether a plant bending toward light or an animal jerking away from something hot. It highlights the immediate change in behavior in response to a cue. Metabolism covers all the chemical reactions that keep an organism alive, not the act of responding to a stimulus. Photosynthesis is the process by which many organisms convert light into chemical energy. Homeostasis is about keeping internal conditions stable. Since the question asks for the term describing the organism’s response to a stimulus, irritability is the best fit because it specifically denotes sensing and reacting to changes.

Responding to environmental changes is called irritability. This captures how living things sense a stimulus and react to it, whether a plant bending toward light or an animal jerking away from something hot. It highlights the immediate change in behavior in response to a cue. Metabolism covers all the chemical reactions that keep an organism alive, not the act of responding to a stimulus. Photosynthesis is the process by which many organisms convert light into chemical energy. Homeostasis is about keeping internal conditions stable. Since the question asks for the term describing the organism’s response to a stimulus, irritability is the best fit because it specifically denotes sensing and reacting to changes.