How do lines in an atomic emission spectrum provide evidence that electrons can only exist in specific energy levels within an atom?

Which are examples of how technology has advanced scientific understanding.1using hot water to sterilize medical equipment.2transplanting a human organ into another individual.3inserting genes from one sheep into another cell to make a cloneunderstanding the different structures that make up a cell.4examining microorganisms from the deepest parts of the ocean

Which statement best describes the flow of energy in this scenario

Avariable that is not being directly tested during an experiment should be