A physical change to a substance can never be reversed

increase or decrease the mass of a substance

changes to type of matter the substance is made of

changes one or more of the physical properties of a substance

4th one

Explanation:

a physical change is something u can see, so if the substance changes its properties then thats a physical change.

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.