Blood Vessels

OPEN SYSTEMS

They work for insects because they are small so blood doesnt have far to travel.  They also have a seperate transport system for transporting oxygen and carbon dioxide

Larger organisms rely on blood however to transport them.  In open systems pressure remains low and slow.  This would not supply the needs to large muscles and would also not transport oxygen etc long distances

CLOSED SYSTEMS

Enables the heart to pump the blood at a higher pressure = flows quicker= delivers quicker and further + removes waste quicker

BLOOD…