Answer:
The early central nervous system begins as a simple neural plate that folds to form a neural groove and then neural tube.
Explanation:
https://embryology.med.unsw.edu.au/embryology/index.php/Neural_System_Development
This model was called GENERAL ADAPTATION SYNDROME [GAS].
Hans Selye proposed the three stages model of GAS, the three stages are alarm, resistance and exhaustion. During the alarm stage, the sympathetic nervous system prepares the body for action. In the resistance stage, the sympathetic nervous system recruits resources that will be needed to maintain high level of activity and energy. In the exhaustion stage,the parasympathetic nervous system takes over and the body experiences physical illnesses.
Answer:
a change from one day to the next day
Ask this in the physics area next time please, but turn to someone you trust or if your young an adult, like your parents or your teachers. Maybe even your friends. No matter what age tell someone and if they don't know then get medical help if they can't.