What is an easy way to measure the volume of an irregular shaped object?

Water displacement

Explanation:

When you put an irregularly shaped object in a graduated cylinder, the water level rises. Subtract the original number of ml from the number of ml it was displaced, and you get its volume.

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.