Draw the structure of a compound of molecular formula c4h8o that has a signal in its 13c nmr spectrum at ≥ 160 ppm. then draw the structure of an isomer with no rings of molecular formula c4h8o that has all of its 13c nmr signals at < 160 ppm.

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.