Theory because a theory is a well substantiated explanation of how a particular phenomenon works based on the set of facts which had been repeatedly confirmed through observations and experiments. A scientific theory gives reliable account of a phenomenon.
Precisely is defined as exactly, specifically or with precision. ... When it is exactly 1:00, this is an example of a time when it is precisely 1:00. When you carefully place books on a shelf with great precision, this is an example of a time when you place the books precisely on the shelf.
