E. coli Bacteria colony. Note that many of these bacilli are undergoing asexual reproduction by binary fission. SEM. — Image by © Dr. Martin Oeggerli/Visuals Unlimited/Corbis

E. coli Bacteria colony. Note that many of these bacilli are undergoing asexual reproduction by binary fission. SEM. — Image by © Dr. Martin Oeggerli/Visuals Unlimited/Corbis