Attached are two images of the diagrams along with the four questions each that I need help answering. Thank you!

Which contributions did galileo make to the model of the solar system? check all that apply. a mathematical model for the orbits of the planets scientifically accurate data on planetary orbits data that showed that planets reflected sunlight similar to earth's moon up the idea that stars are other suns that do not move u observations of the moons of jupiter rotating around the gas giant

Which of these is not an obstical to the future of space exploration? fundingresearch ideas technologytime

Are the brightest stars low magnitude or high magnitude?