Which is true of all covalent compounds?​

 All covalent compounds share electrons in bonds. They are made of two or more nonmetals which share electrons. They do not form ions, charged particles, so they are not good conductors in water.

Explanation:

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.