Simplify the following text for a Grade 9 native English-speaking person.
Original: Overall health is achieved through a combination of physical , mental , and social well-being , which , together is commonly referred to as the Health Triangle .
Simplified: Health is `` a state of complete physical , mental , and social well-being and not merely the absence of disease or infirmity '' , according to the World Health Organization ( WHO ) . Physical is about the body .