'Although speech is the most advanced form of communication, there are many ways of communication without using speech. Signals, sings, symbols and gestures may be found in every known culture. The basic function of a signal is to impinge upon the environment in such a way that attracts attention, as for example, the dots and dashes of a telegraph circuit.' What does the author say about speech?
A. it is the only true form of expression.
B. it is dependent upon the advances made by inventors
