Explanation:

* Core idea: Living organisms change over time through a process of natural selection, where individuals with traits better suited to their environment are more likely to survive and reproduce.

* Evidence: Fossils, genetic comparisons, observation of evolution in action (e.g., antibiotic resistance in bacteria), and other fields of study.

* Predictions: The theory predicts that organisms will adapt to their environments over time, leading to the diversification of life.

* Importance: This theory provides a framework for understanding the diversity and history of life on Earth, and has profound implications for medicine, agriculture, and conservation.

Key Features of a Scientific Theory:

* Explanatory power: Provides a coherent explanation for a wide range of observations.

* Testability: Can be tested and falsified through experimentation and observation.

* Predictive power: Can make predictions about future observations.

* Supported by evidence: Based on a large body of empirical data.

Note: Scientific theories are not simply guesses or speculations. They are well-substantiated explanations that have been rigorously tested and supported by evidence. They are constantly being refined and updated as new evidence emerges.