Examples from literature

• The amoebae, one celled animals, smaller than a small pin-head, have existed unchanged since life began. 
• These conditions he has shared with all forms of life from the amoeba to the civilized nation. 
• Up to the present it has been assumed that the environment of the amoeba is that to which it has become adapted and which is favorable to its existence. 
• We have the one-celled amoeba, the microscopic animals, and the lowest forms of animal life. 
• When such a bacterium comes in contact with an amoeba, it is taken into its body by becoming enclosed in processes which the amoeba sends out.