Final answer:
A statement explaining the current form or past existence of something within the natural universe is called a scientific theory, which is a substantiated principle based on comprehensive evidence and testing.
Step-by-step explanation:
A statement of how something is done or why it exists in its present or past form is often referred to as a scientific theory. In science, a theory is a well-substantiated explanation acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation. Such theories are composed of facts, laws, predictions, and tested hypotheses that are widely accepted within the scientific community. For instance, in chemistry, the statement "All matter is composed of atoms" serves as a foundational theory explaining a vast array of observations. Therefore, when we refer to "the theory of something," we convey a comprehensive and extensively corroborated statement that represents our present understanding of a phenomenon within the natural universe.