You don't need both. GPE is the gravitational potential energy caused by the fact that an object is not touching the ground of the earth. KE is caused by an object moving. This problem says that the bowling ball "sits" meaning that you only need the GPE because it's not moving and it is not touching the surface. You would use the GPE equation to find how much Potential energy an object has. If you want its velocity, you would set the answer to the GPE equation equal to the KE equation to find its velocity.
4) Isaac Newton was the first scientist to propose the idea that gravity increases distance between objects decrease
Explanation:
1 - Kepler may have inspired most of Newton's propositions, but there is no record of collaborating on the theory of universal gravitation.
2 - The universal gravitation theory resemble the works of other great scientists, but Newton was indeed the first to propose this idea of gravitation
3 - On the contrary, these scientists have shared concepts, with differences in accuracy that supersede each other to be accepted by the community (i.e: Einstein being at the forefront despite sharing some ideas with Newton)