How come concussions are bad for you?

Can someone give me one specific health problem (within unhealthy eating) and explain it. !

How is health different for most people in this country today from what it was for people born in 1900? a. people have a shorter life span. b. people today work harder to survive. c. people today live in poorer sanitary conditions. d. people today can focus less on day-to-day survival and more quality of life.

Burns are devastating and debilitating because of loss of fluids and electrolytes from the body. how do physicians estimate the extent of burn damage associated with such dangerous fluid loss?