What is the difference between theory and certainty to a scientist?

In each module, you will be participating in a Question and Answer chain.

The first student to respond to the First Question, will then post a question of their own. The first student to answer that question will post the next question, and so on. Thereby creating a Question and Answer chain.

Weekly Topic: Properties and Hierarchies of Life

First Question: What is the difference between theory and certainty to a scientist?