Scientists are calling for urgent action on free-living amoebas – a little-known group of microbes that could pose a growing global health threat. Here's what you need to know. Free-living amoebas are single-celled organisms that don't need a host to live . They are found in soil and water , from puddles to lakes. What makes them remarkable is their ability to change shape and move using temporary arm-like extensions called pseudopodia – literally "false feet". This allows them to thrive in an