The IndexError: list index out of range error occurs in Python when an item from a list is attempted to be accessed that is outside the index range of the list. The range of a list in Python is , where n is the number of elements in the list.
Parallel processing in computers is like having an efficient team working on different parts of a task simultaneously. In traditional programming, tasks are executed one after the other, like solving a puzzle piece by piece. However, parallel processing divides the task into smaller chunks, and these chunks are handled simultaneously by multiple processors or cores. Python provides modules that allow programs to leverage multiple processor cores efficiently.