You add 6.5 g of iron to 25.50 mL of water and observe that the volume of iron and water together
is 26.33 mL . Calculate the density of iron.
Express your answer to two significant figures
with the appropriate units.

the answer is c i took the test

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.