Answer:

monitors

Answer	Crossword Clue
MONITORS	Keeps track of
MONITORS	Hall pass checkers
MONITORS	Computer screens

MONITORS	Keeps an eye on
MONITORS	Selected students.
MONITORS	Checks on radio or TV transmitters.
MONITORS	Large lizards.
MONITORS	Proctors.
MONITORS	Regulates.
MONITORS	Teachers' helpers
MONITORS	Security office array