Answer:
Proton proton chain reaction involves the fusion of two hydrogen atoms.
Step-by-step explanation:
Two protons combine together to form a deuterium nucleus, a neutrino and a positron.
This deuterium will then combine with another hydrogen to form a helium isotope with mass number three and gamma rays.
Now two helium isotopes combine to form a helium 4 nucleus and two protons.
These two protons will once again initiate another proton proton cycle.
These are called thermonuclear fusion reactions. They are responsible for the heat and light that are received from sun .
Proton proton cycle happens in all stars primarily.