Answer: The first step of hydrogen fusion reaction is given below.
Step-by-step explanation:
Fusion reaction is defined as the nuclear reaction in which lighter nuclei fuses together to form a heavier nuclei.
Hydrogen fusion process is the process in which hydrogen atoms fuses together to produce helium as the end product.
The equations representing hydrogen fusion process is:
Step 1: Fusion of 2 hydrogen atoms to form deuterium atom.

Step 2: Fusion of deuterium and hydrogen atom to form Helium -3 isotope

Step 3: Fusion of helium-3 isotope with hydrogen atom to produce helium-4 atom.

Hence, the first step in this hydrogen fusion process is
