In MLA when you need to create an in-text citation of a paraphrase, it is necessary to indicate the source by including the author and the page number. Since you did not include the author of the article or any passage to cite specifically, here are some formats you could follow:
According to <em>name of the author</em>, "passage in quotations" (<em>56</em>).
"Passage in quotations" (<em>name of author 56</em>).
Essentially, you need to include the passage in quotations and can add whatever else you need to to your sentence. In the first format, you include the author's name within the sentence, so you don't need to include it at the end. The rest of the information, like the title of the article or the date it was published does not need to be included in an in-text citation, but must be included in your reference list.
Darwin's argument tells us that species develop their traits through natural selection due to competition, survival and reproduction. Diversification of species is an important part to make his argument valid because diversification suggest extinction of specie if it doesn't survive.
