ur senses
it might be sick or in pain
It is called narcolepsy.
earthquakes
Not being able to control your body like that getting a "shake" could be an epileptic seizure indeed, but it could also be much more ;-)
This body movement during sleep, known as a hypnic jerk, is believed to be a natural occurrence when the body transitions from wakefulness to sleep. It is thought to be due to a sudden change in muscle activity as the body relaxes.
I think its called Tourettes syndrome
It is not accurate to attribute someone's behavior or personality traits to a specific chromosome. Human behavior is influenced by a combination of genetic, environmental, and social factors.
the earths gravitiy causes it to push down
We jerk a clinical thermometer to ensure that the mercury or alcohol inside is at the lowest point on the scale before use. This makes sure that we get an accurate measurement of body temperature when placed in the mouth, under the arm, or in the rectum. Jerking the thermometer helps to reset the mercury column to the starting position for a new reading.
It means he's a jerk and should be avoided.
it would go slower and it might jerk