they just do it. it is an instinkt.
They react in same way most animals do. They respond to any stimulus. The stimulus can be touch, smell, sight etc... Blue Whales are likely to not to respond to same things as humans such as touch but still react to stimulus. An example being swimming deeper when a boat is near by.
An organism reacts to a stimulus with a response that aims to maintain homeostasis and ensure survival. This response can be behavioral, physiological, or molecular, depending on the type and intensity of the stimulus.
does the same organism always react to the same stimulus at the same way
stimulus
running from the object
Thermoreceptors react to changes in temperature, either hot or cold, in their surrounding environment. They send signals to the brain when there is a difference in temperature to help regulate the body's temperature.
stimulus
stimulus
A stimulus. ("stimuli" is the plural)
stimulus
A stimulus causes your body to react, a response is something that is caused by a stimulus. Work it out, does the virus respond to you more or you to the virus?
The change is actually a stimulus and when the organism reacts to the stimulus, it becomes a response. Overall, The answer is a stimulus.