Answer:
areas of high pressure to areas of low pressure
Stimulus is something that causes a psychological response. It can be internal or external. The stimulus is the contact with the hot pan. It is an external stimulus. Sense organs, such as the sensory receptors in the skin are sensitive to external stimulus. The quickly pull of your hand is a reflex action.
The contact causes a nerve impulse that will travel to the spinal cord via the sensory neurons.<span>To respond to the stimulus of the reflex arc, the muscle needs to contract to pull the hand quickly away from the hot pan.</span>
1. Testing only one variable
A controlled variable means its the one that stays the same. In a controlled experiment, it means there is only one manipulated, (changed) variable.
Thick rigid cell wall is not characteristic of a parenchyma cell
