Microorganisms

The meat, although cooked, isn't completely free of microorganisms.

If martians exist, they would probably be microorganisms.

Antibiotics fight the development of microorganisms.

Bacteria are microorganisms.

The ultraviolet light disinfects wastewater so completely that bacteria and other harmful microorganisms cannot grow.

Scientists say that each tropical disease is notoriously difficult to treat, because the microorganisms evade the immune system by changing their appearance frequently.

The fluid contains alien microorganisms.

Martino showed the alien microorganisms to Rima.

The microorganisms have evolved into large insects.

The alien microorganisms started to mutate and grow.