Where does the process reside in memory?
A process is not a single data structure. In the Windows operating system, for example, a running process has a number of different structures in its memory including a copy of its PE header and its environment variables. Here is a table from a debugger showing the layout of one process after it has been loaded into memory:



The various pieces of data have different structures. For example, the PE header is a record, but the heap is usually some kind of tree or list.