Question

How can platyhelmenthes exhibit both organ level and organ system levels of organizations as mentioned in NCERT text book?

Answer 1

If compared with higher-order phyla, we can see that Platyhelminthes do not have well-accomplished organ systems.
There are many organs systems existing in advanced phyla such as the circulatory system, respiratory system, digestive one, muscular, etc. But Platyhelminthes do not have all these organ systems developed, so the organization is supposed to be organ level one. But their digestive system is complete, and they also have a simple level of the nervous system, that has brain and nerves, so at some level, they are also known to exhibit an organ system level of organization as well.