2. An amino acid with three ionizable functional groups can exist in different forms and histidine is an example. [17 pts.] (a) Draw the structures of the predominant ionization state of histidine at pH 1, 4, 8 and 12. Include the net charge on the histidine molecule in each ionization state. (b) Write the equilibrium equations for the three ionizable protons present in histidine an assign the proper pKa for each ionization.

b i think it’s a water wheel turning in a stream

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.