When it was found that, without the force of gravity exerting pressure on the bones, bone mass was lost in astronauts, what kind of exercise provided an antidote?

The four Science Regents exams (Earth Science, Living Environment, Chemistry, and Physics) also include separately-scheduled lab practicals.
In New York, students have the opportunity to take Regents Exams in grades 9-12 and, when appropriate, in grade eight.