Answer
In order for scientists to prove they found life on another planet, they would have to demonstrate the organism they found is capable of replicating, acquiring and using energy, processing information, and evolving.
Work Step by Step
To be able to prove that the organism they have found on another planet is, in fact, a living one, it would have to reproduce and respond to its environment. If an organism is unable to reproduce it cannot be categorized as living since all living organism must reproduce in either a sexual or asexual way. The found organism must able to respond to its environment through means of taking in signals depending on environmental conditions and developing adaptations suited for their environment through the process of evolution.
