The correct answer should be additionally.
The word additionally would provide the best transition between these two sentence. It is so because you have one idea in the first sentence, and then you want to show another idea very similar to the first one in the second sentence. Using additionally to convey that is the way to go.
Answer:
Johnson's intended audience was his fellow lexicographers. Throughout the text, he responds to the efforts of authors and academics who are also trying to standardize the language, particularly Johnathan Swift.
(PLATO answer)
Typically in the introduction paragraph, the first sentence in the essay is the topic sentence.
