Jeez... if there was an "all of the above" option for 1, that would be correct. But, out of the selection, I would say:
1. D
2. B
Those would be my selections because (1) investigations can lead to huge discoveries that may impact the world, and (2) when a scientist conducts and experiment, it can lead to even more discoveries and more facts and evidence, then they can pose questions about what they have observed and communicate with scientists about that observation to give them an idea of what could happen.