1 Nitrogen Fixing.
2 Decomposition and Ammonification.
3 Nitrification.
4 Denitrifying bacteria.
Bro im jus gonna be straight up w you i want to help you but i cant becuase i have no idea what that is
Answer:
nuclear fusion
Explanation:
When the density and temperature at the core of the gravitationally collapsing nebula reaches values when nuclear fusion is triggered and sustained, that marks the birth of the star.