Your teacher was given an apple by a student trying to get on her good side. it sits on her desk the whole year, not moving. you know that, if the apple were to roll off the desk, it would fall to the ground. so what is keeping the apple motionless on the desk? a) once placed on the desk, gravity is no longer acting on the apple. b) the downward force of gravity on the apple is balanced by a larger force on the apple by the desk. c) the downward force of gravity on the apple is balanced by an equal but opposite force on the apple by the desk. d) the downward force of gravity on the apple is balanced by an equal but opposite force on the apple by the teacher.