Question

Does urochordata have open circulatory system ?
ncert writes chordates have closed but does not mention any exception so what to answer in NEET?

Answer 1

Open They have a tubular heart with either no chambers or 1 chamber (depending on the source) Their heart contains no values and it uses perstaltic contractions. It also has no endocardium. They have blood (but it also referred to as hemolymph by some sources) with hemocytes but their blood does not contain hemoglobin, although their genome does contain 4 hemoglobin genes. They do have hemocyanin (an "alternative" to hemoglobin for transportin oxygen) but it might not be used for oxygen transport. Their circulatory system is open, but may have many vessels; the extent to which vessels are lined with endothelium is unclear.