Which of the following is an external stimuli?(1 point)
Responses
gravity
gravity
dehydration
dehydration
nutrients in a cell
nutrients in a cell
body temperature
body temperature
What stimulus could trigger a fight or flight response?(1 point)
Responses
temperature change
temperature change
geomagnetic information
geomagnetic information
seasonal change
seasonal change
sensory information
sensory information
sensory information
What stimulus causes plant roots to grow downward?(1 point)
Responses
temperature
temperature
gravity
gravity
light
light
pollution
gravity
Which of the following is an internal stimuli?(1 point)
Responses
habitat pollution
habitat pollution
water in a cell
water in a cell
amount of daylight
amount of daylight
habitat temperature
water in a cell
What is the process of maintaining a stable internal environment in an organism?(1 point)
Responses
stimulus
stimulus
homeostasis
homeostasis
phototropism
phototropism
response
homeostasis
To determine which of the following is an external stimulus, we need to understand the definition of an external stimulus. An external stimulus is any physical or chemical change in the external environment that can be detected by an organism and can elicit a response.
Looking at the options given:
1. Gravity: Gravity is not an external stimulus. It is a constant force acting on all objects and organisms on Earth, and organisms have adapted to live and function in a gravitational environment. Therefore, it does not create a detectable change that elicits a response.
2. Dehydration: Dehydration can be considered an external stimulus. When an organism is exposed to a lack of water in its external environment, the decrease in water availability can be detected by its cells and trigger various physiological responses, such as increased thirst or the release of anti-diuretic hormone.
3. Nutrients in a cell: Nutrients in a cell are not an external stimulus. Instead, they are internal factors that are used by the cell for its metabolic processes. Nutrient availability inside a cell does not create a detectable change from the external environment.
4. Body temperature: Body temperature is not an external stimulus. It is an internal factor within an organism. While changes in body temperature can be influenced by external temperature or thermal environment, body temperature itself is not considered an external stimulus.
Therefore, the correct answer is "dehydration" as it is the external stimulus from the options provided.