In attempting to avoid short, choppy sentences, writers sometimes go to the opposite extreme, putting more subordinate ideas into a sentence than its structure can bear. If a sentence collapses of its own weight, occasionally it can be restructured. More often, however, such sentences must be divided.

Excessive subordination makes it difficult for the reader to focus on the quoted passage. By splitting the original sentence into two separate sentences, the writer draws attention to Peter Singer’s main claim, that humans should give “equal consideration to animals.” (See MLA-4a on citing sources in MLA style.)