Single-celled organism with the ability to change shape (6)

I believe the answer is:

amoeba

(Other definitions for amoeba that I've seen before include "Unicellular organism" , "Simple life form" , "Single-celled form of life of ever-changing shape" , "Microscopic organism of single cell constantly changing shape" , "Microscopic organism of single cell that changes shape constantly" .)

I've seen this clue in The Times.

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