Answer:
Sentence
Step-by-step explanation:
A sentence is a group of words that contains a subject and a verb with a complete thought. A sentence can be declarative, imperative, interrogative, or exclamatory. The group of one word 'Sit!' forms a sentence because it contains the verb 'sit' and the subject 'you' is understood. This is an imperative sentence, which has the purpose to give a command. Example: "Go!" , "Stop!"