Lara's mouth is dry, and she realizes that she hasn't had anything to drink all morning. The water level in her
cells has dropped, and she feels thirsty. Seeing her classmates drinking from their water bottles is
distracting her from paying attention in class, and at the next opportunity, she will go to the water fountain
and take an extra large drink. Her feeling thirsty and taking an extra large drink can be understood in terms
of the _____ theory of motivation.