I think the answer is D. ( or supported by observations ). Because theories change over time, they both NEED to be proven, they do NOT go off of consensus, but they do NEED to be supported by observations. I hope this helps.
Theories may increase over time. Universal laws are thought to not change.Most theories and laws cannot be positively proved and they are continually tested.The consensus is not required. Many theories were dismissed by the preponderance of the scientific community before been taken. Both theories and laws must be based on an accurate method and measurements are a key part of it.
So sound travels 1 kilometer in roughly 3 seconds and 1 mile in roughly 5 seconds. When you see the flash of a lightning bolt, you can start counting seconds and then divide to see how far away the lightning struck.
