A molecule is made of more than one atom of differing elements that can be simplified while an element cannot be simplified because it is only one atom of one type of element.
Explanation:
I hope the diagram will help remember A always pairs with T and C always pairs with G. u can also remember as Apple Tree and Car Garage. :)
In the outer shell. So, A the outer level.
I hope that this helps.
Answer:
The answer is 4th one as I think