Answer: Lungs
Explanation: The pleura encloses each lung by a double layered serous membrane
What is the question so we can help
Three important characteristics such as a notochord, a dorsal hollow nerve cord, and pharyngeal gill slits, should appear at any stage of their life cycle. These are the characteristics of the chordates. Members of echinoderms share resemblance with chordates in presence of a notochord.
I think it’s B. I think this cause meiosis is the cell multiplying