Answer: the smallest particle of an element is called an atom.
Compounds can be broken down to simpler substance through the process called Chemical Reaction, I think.
In the universe, _______ makes up 75% of all matter, _______ makes up abut 20% and ________ being the 3rd (5%) most abundant element.
Answer is
In the universe (hydrogen) makes up 75%
and (Helium) makes up about 20%
and (oxygen) being the 3rd makes up (5%)
Step-by-step explanation: Hope this helped :)
