The topic in the third sentence connects backward and prepares the reader for the upcoming information.
This revision shortens the sentence and identifies the performers.
However, the original passive style creates parallel structure by repeating the topic of the second sentence ("This structure has...") in the third sentence ("A structure for...").
Whether in the Methods or elsewhere in a manuscript, the passive voice redirects attention to the action (or the recipient).
Choosing a passive writing style is sometimes necessary to position important information at the beginning or end of a sentence.
When discussing an experimental procedure in the Methods section, a researcher might write: The sentences could be converted to active voice by writing the following: We kept the honey bees in a humidified chamber at room temperature overnight. (In fact, the second sentence is one word longer than it is in the original version.