facts and statistics collected together for reference or analysis

is a transitional stage of physical and psychological development that generally occurs during the period from puberty to adulthood.

a circumstance, fact, or influence that contributes to a result or outcome.

is a general term to describe a state caused by inadequate quantity or quality of sleep, including voluntary or involuntary sleeplessness and circadian rhythm

the body's chemical messengers, sending signals into the bloodstream and tissues.

the time in life when a boy or girl becomes sexually mature.