Final answer:
Good scientific theories explain a wide range of observations and phenomena through well-supported explanations based on substantial and repeated evidence. They are not guesses but rigorous conclusions thoroughly tested and verified.
Step-by-step explanation:
In science, good scientific theories are so important because they organize and explain a wide range of observations and phenomena. This means that the correct answer to the question is option d) from the provided choices. A scientific theory is a well-supported explanation for natural phenomena that is backed by a substantial body of evidence obtained from repeated observations and experiments. It's important to note that scientific theories are not mere guesses or assumptions; they are robust conclusions that have been rigorously tested and verified through scientific evidence by the scientific community.
For instance, the theory of biological evolution explains how species change over time based on evidence from fossils, genetic data, and observations of living organisms. Similarly, the germ theory of disease posits that microorganisms are responsible for causing many diseases, which is supported by a plethora of microbiological research.