A non scientific question is a question which cannot be proved to be true as no experiment or no data can be gathered from it. Why are roses the best flowers? is an example of nonscientific question. The answer of this question is subjective and it brings no scientific data. Scientific question on the other hand is a question that may lead to a hypothesis and help us in answering (or figuring out) the reason for some observation.
The distance of the Goldilocks zone ensures that water on the terrestrial planet is maintained in the liquid phase. This is because the distance from the star ensure it receives enough sunlight to keep the planet warm but not too hot that the water exists as vapor. Water in its liquid form is essential for maintaining life like here on earth.