A．people under stress tend to have a poor memory
B．people who can't get their job done experience more stress
C．doing challenging work may be good for one's health
D．stress will weaken the body's defense against sperms

A．a person's memory is determined by the level of hormones in his body
B．stress hormones have lasting positive effects on the brain
C．short bursts of stress hormones enhance memory function
D．a person's memory improves with continued experience of stress