jellyfish
Jellyfish have a simple digestive system. They have a digestive cavity with cells lining the wall that carry out the digestive function.
All living organisms have a very complex chemistry.
The specializations that are common in the digestive tract of higher organisms such as humans is complex. It includes highly-specific digestive enzymes.
Flatworm
I had asked the same thing before but then I figured it out. Out of a flatworm, sponge, coral, or crab, the complex invertebrate is a crab.
No a worm is more complex than a jellyfish
Jellyfish were not even alive during the Precambrian era because only single-celled organisms lived.
I am pretty sure they have simple but very complex digestive systems
advantages of human beings are complex organisms
Complex organisms need cells that perform many different functions. Complex organisms are capable of a lot of different things, and that variety needs to be supported on the cellular level. Without them, complex organisms cannot perform different functions.
System
Complex organisms need cells that perform many different functions. Complex organisms are capable of a lot of different things, and that variety needs to be supported on the cellular level. Without them, complex organisms cannot perform different functions.