题目内容：
根据以下材料回答第 1～4 题：Passage Three
Ever since human inhabited the earth，they have made use of various forms of communidation．Generally，this expression of thoughts and feelings has been in the form of oral sDeech．When there is a language barrier，communication is accomplished through sign laPguage in which motions stand for letters，words and ideas．Tourists，the deaf and the mdte have to use this form of expression．Many of these symbols of whole words are very pigturesque and exact and can be used internationally；spellin9，however，cannot．
Body language transmits ideas or thoughts by certain actions，either intentionally or unintentionally．A wink can be a way of flirting or indication that the person is only jok ing．A nod signfies approval，while shaking the head indicates a negative reaction.
Other forms of nonlinguis tic language can be found in Braille(a system of raised dots read with the finger tips)，signal flags．Morse code and smoke signals．Road maps and pigture signs also guide，warn and instruct people．
While verbalization is the most common form of language，other systems and tech—nidues also express human thoughts and feelings．
Which of the following best summarizes this passage?
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