Choose the sentence that is not logically connected in the paragraph. (1) one final effect of radio and tv on the language must must be noted. (2) there is no doubt that these great media of information have cut down considerably the time that used to be devoted to reading. (3) radio and tv may enhance the spoken word. (4) they tend to lower comprehension levels.

The sentence that is not logically connected in the paragraph is 4).

There must be no period after "word" in order to logically connect sentence 4) to sentence 3) by means of the word "but" preceded by a comma ("Radio and TV may enhance the spoken word, but they tend to lower comprehension levels"). "But" has to be added in order to connect two ideas that contrast (radio and TV may have a positive impact, but they can also have a negative impact).