Could invisible aliens really exist among us? An astrobiologist explains
Monday, January 13, 2020 - 08:00
in Biology & Nature
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.