Because they feel like life doesn't matter anymore. maybe they have been through a lot amd can't deal with it anymore and they are to afraid to ask for help. a lot of people who get bullied feel as though they should give up.
Answer:
d and wut class are you taking
The time it takes to move in responce to a stimulus is called the reaction time
One of the biggest concerns in doctors that I have seen from watching TV is that flu pandemics if left untreated can turn deadly not within a matter of days but within a matter of minutes. Hope this helped.