Answer:
b. The step stool exerts a force on the student in the opposite direction of gravity.
c. A student exerts an upward force on the step stool equal to the gravitational force
Step-by-step explanation:
It is true that gravity is the force that pulls the objects down to the earth but there are some forces that oppose the statement.
In the given situation, the student is unable to fall down from step stool is because of two forces one, the force exetred by step stool on student and two, the force exerted by the student on step stool.
The step stool exerts a force on the student in the opposite direction of gravity that gives stability to the step stool and an upward force on the step stool equal to the gravitational force helps the student to climb the stool.
Hence, the correct option are b and c.