0 a very small, simple organism consisting of only one cell --
1 a type of organism that has one cell --
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.
We have the one-celled amoeba, the microscopic animals, and the lowest forms of animal life.
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.
These conditions he has shared with all forms of life from the amoeba to the civilized nation.
The amoebae, one celled animals, smaller than a small pin-head, have existed unchanged since life began.
