Could invisible aliens really exist among us? An astrobiologist explains

Life is pretty easy to recognise. It moves, it grows, it eats, it excretes, it reproduces. Simple. In biology, researchers often use the acronym “MRSGREN” to describe it. It stands for movement, respiration, sensitivity, growth, reproduction, excretion and nutrition… Read more about the topic here in the link below… https://theconversation.com/amp/could-invisible-aliens-really-exist-among-us-an-astrobiologist-explains-129419

Read More Could invisible aliens really exist among us? An astrobiologist explains