Final answer:
Scientific explanations are subject to change due to new observations, technological advancements, and the need for testing and refining hypotheses through experimentation. Hence, d) is correct.
Step-by-step explanation:
Scientific explanations are subject to change because new observations and developments in technology can lead to a better understanding of a phenomenon or contradict previously accepted explanations. Scientists are constantly testing and revising their ideas based on new evidence.
While scientific explanations are not just a best guess, they are hypotheses that can be tested and refined through experimentation.