What is it?
Open Circulatory System Watch
- Thread Starter
- 07-03-2016 22:27
Offline18ReputationRep:TSR Support Team
- TSR Support Team
- 09-03-2016 15:26
Humans have a closed one - the blood does not come into contact with the tissues.
An open one, the "haemolymph" - similar to blood - comes into contact with the tissue directly.
Have a look on YouTube too. Some good videos there.