Understanding the serial implementation of the calls

#1

When a particular call is witnessed and there is another recursive function call after it, are the calls implemented simultaneously or one by one.

#2

hello @gargprachi1203 all the recursion calls stay in the call stack memort but they are not parallel .
i.e it calls another call and reach teh base case and then on returning back it finalise the result for the previous calls that were in the call stacks .
Happy Learning !!