The Rock says

Opensource software is a software where users will have access to the source code. Users can view the code and modify according to their business needs.

Regarding Closed source software, you never know what kind of code had been written. Users will not have access to the source code. Users can only have access to use the software.

Is access to source code generally required?
Mostly No. Not most of the users bother to view source code. They need the application working.

But what if the user wants to change colors or wordings,?
In this case, having source code is defnitely an advantage. Access to source code defnitely gives you points over not having source code at all.

What if user tries to modify the source code without having full knowledge of it?
The application corrupts and may not work. There is a channce that your application is corrupted by changing code without an idea. You need to make sure the access to source code is restricted to only to those people who have knowledge of it. This is nothing but one sort of closed source in open source software.

Overall, No one scores over other. Closed source software is something which is there from the beginning or popular from long time. Open source software is the innovation or something which is upcoming now. Comparing both these is not actually a good idea, because one is opposite to other. Disadvantages of one is advantages of the other one. So there is no question of comparison. Both are good and useful in their own ways.