Solid aluminum Aland oxygen O2 gas react to form solid aluminum oxide Al2O3. Suppose you have 1.0 mol of Al and 11.0 mol of O2 in a reactor

there are two significant figures.

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.