Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.
 
        
                    
             
        
        
        
Answer:
Plasmin
Explanation:
Plasmin is a serine protease also referred to as fibrin digesting enzyme, it is responsible for the dissolving or degradation of blood clot. The process by which plasmin degrades blood clot is called fibrinolysis. Note that plasmin (active) is formed from an inactive enzyme called plasminogen.
 
        
             
        
        
        
Answer:
C
Explanation:
C is what the circulitory system dosent do so its C :) Sorry, i sent this a bit late.