Environmental factors describe reactions to stimuli such as which?

• A. Sound and light
• B. Temperature only
• C. Humidity alone
• D. Altitude changes

Answer: (A)

Reactions to environmental stimuli are driven by the senses that detect what’s around us. Sound and light are classic examples because there are specialized receptors for them—the ears and the eyes—that quickly convert those external signals into neural messages. When you hear a sudden noise or see a bright flash, your nervous system triggers rapid responses like turning your head toward the source, blinking, or adjusting your focus and pupil size.

Other options like temperature, humidity, or altitude are indeed environmental factors, but they often influence us more gradually, prompting physiological adjustments rather than the immediate sensory-driven reactions typical of sound and light.