Hypothesize an evolutionary relationship among the bipinnaria larva of echinoderms, larval and adult tunicates, and lancelets

The first stage in the larval development of most of the starfish is bipinnarial.It is usually followed by abrachiolaria stage.Its movement and feeding is accomplished by the bands of cilia.Starfish that breed their young generally lack a

bipinnaria stage, with the eggs developing directly into miniature adults.

Tunicates which are large group of marine animals , and their recent common ancestry with tadpoles is reflected in the tadpole-like larvae of most tunicates.They are also called as urochordates.

Fish like chordate,lancelet and amphioxi respire mostly through the skin.The use of gill slits for feeding rather than respiration is characteristic of the lower chordates.

as many times as you want

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%