One of the most important principles in biology is that all living things must come from other living things. This principle was not discovered until the eighteenth century. Before that, people believed that life could come from nonliving matter. For example they thought that worms could come from meat. Then an Italian scientist named Francesco Redi tried an experiment. He covered some meat with a cloth so that flies could not land on it. When no worms grew on the meat, he knew that the worms really came from
scientists.
the cloth.
fly eggs.
the meat