How can we sure that a possible source of uncertainty is the same as a source of error? I've always thought that to a small extent, there can be differences in experiments due to randomness. In such case it wouldn't be error--the differences this randomness creates would simple be statistical noise. If an experiment does control for a certain variable, would it be experimental error, systematic error, human error...?

In the realm of science, it is incredibly difficult to prove something is right. Using the scientific method, we can prove many things to not be right, but we cannot single out one true path to answer a hypothesis. In most cases, there are numerous 'correct' methods.

What sort of renewable energy technologies would require biology? Off the top of my head, it feels like solar, wind, hydroelectric, geothermal, and nuclear power do not have a direct relationship with biology. I am curious.