【正确答案】：
THE MINIMAL MEANINGFUL UNITS ARE KNOWN AS MORPHEMES. IN OTHER WORDS, THE MORPHEME IS ‘THE SMALLEST FUNCTIONING UNIT IN THE COMPOSITION OF WORDS’. 
【题目解析】：The minimal meaningful units are known as morphemes. In other words, the morpheme is ‘the smallest functioning unit in the composition of words’. 最小的意义单位叫做“词素”。换句话说，词素是“词语中最小的功能单位”。