What are 2 characteristics of a scientific theory?

It is provisional (so only holds until proved incorrect, or 'falsified').

It is based on, often hidden, fundamental assumptions and beliefs.

There are a number of others.

i.e. It is often based on a mathematical abstraction of a limited part of nature.

It is normally founded on interpretations of observations, which are consistent with much of the evidence, but rarely all.

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Here are three slightly different:

1) It is based on observation and experiment.

2) If observations and experiments continue to support the theory, it may become widely accepted.

3) If it becomes widely accepted, it may be used to explain and possibly predict natural phenomena.