Basically, the P-P chain turns 4 protons into: 1 neutrino, 1 gamma ray, 1 positron, 1 helium nucleus. 
A gamma ray = energy. 
The chain converts hydrogen into helium and makes energy. 
This is all occurring through fusion reactions where 2 protons basically smash into each other. But, it could also be e.g. a proton smashing with a deuterium nucleus. Or, other nuclei smashing together to make something else.
Hope this helps! 
        
             
        
        
        
D. The umbilicus is caudal to the chin
The terms caudal and inferior are synonymous, meaning "away from the head end or toward the lower part of a structure or the body; below." The umbilicus is caudal (inferior) to the chin.
        
             
        
        
        
When the nurse gives you a shot, the Vaccine release white blood cells that fights flu viruses, you can stay happy and healthy!