Answer:
Because in 9/11, airplanes were hacked. They had to upgrade cyber-security and networks so nothing like that happens again.
Explanation:
Bone marrow, is one but I don't know any else off the top of my head
It’s called weight fluctuation. you physically can not gain weight in one day. you only gain weight by consuming more calories than your general caloric intake. for example, the basic calorie intake is 2000 calories a day. you would have to eat well over 2000 calories in one day to gain weight, successfully.
A lifestyle is the way a person chooses to live, so the answer would be priority, personal choice, habit.