A student makes a model of the sun-Earth system by swinging a ball around her head. Using this model, the student is trying to explain how Earth stays on a path around the sun. The student explains that this path is the result of: A. the magnetic attraction between Earth and the sun. B. potential energy stored in Earth that originated in the sun. C. the gravitational attraction between the sun and Earth. D. electromagnetic energy from the sun pulling on the Earth.

The gravitational attraction between the Sun and the Earth is exactly modeled by the tension in the string.  (C)

This is an excellent demonstration !  It shows:

-- If she uses a heavier ball (more mass), she gets more tension in the string, just like planets.

-- If she wants the ball (planet) to revolve faster, she has to increase the tension in the string.

-- If she lets out a longer string, the ball moves slower, and there's less tension in the string, just like planets.

-- The ball stays in the same plane all the way around, just like planets.

b) 10 minutes

girls stopped for 10 minutes.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba