Answer:
Nitrogen
Explanation:
Nitrogen is the most abundant element in our atmosphere and 7th most abundant in the universe. It is vital in the formation of nitrogenous bases which are the key bonds that form nucleic acids such RNA and DNA.
The correct order is -
Vessel spasm; plug formation; coagulation
A vascular spasm or vessel spasm is a sudden tightening of a blood vessel. The platelet plug or also called hemostatic plug formation is an accumulation of platelets formed in response to blood vessel wall injury. And coagulation or clotting is the process in which blood changes from a liquid to a gel thus forming a blood clot.
<span>Gill arches of jawless fishes</span>
