Which of the following best describes Professor Hall’s relationship with his students

A．Members of a species differ from one another.
B．differences between individuals are inherited.
C．Two organisms with identical genes may grow to different sizes.
D．More organisms are born than live to reproduce.

A．widespread concern over its harmful effects
B．great panic over the mental disorder it could cause
C．an intensive research into stress-related illnesses
D．popular avoidance of stressful jobs