* Is supported by a large body of evidence. This evidence comes from multiple sources, including experiments, observations, and data analysis.

* Is consistent with existing scientific knowledge. It shouldn't contradict well-established principles or laws.

* Can be tested and potentially falsified. This means that there must be ways to design experiments or observations that could disprove the theory.

* Is the most parsimonious explanation. This means that it is the simplest explanation that accounts for all the available evidence.

* Is predictive. It can be used to make predictions about future observations or phenomena.

Important Note: A scientific theory is not a guess or an opinion. It is a well-supported explanation for a natural phenomenon. Theories can be modified or even replaced over time as new evidence emerges, but they are always grounded in rigorous scientific inquiry.