What is the difference between shallow copy and deep copy?

The distinction between shallow copy and deep copy in Python primarily revolves around how objects are duplicated in memory. A shallow copy creates a new object, but it copies references to the objects contained in the original object rather than copying the actual objects themselves. This means that changes made to any of the nested objects in the shallow copy will also reflect in the original object, since both share references to the same nested objects.

On the other hand, a deep copy creates a new object and recursively copies all objects found in the original object. This means that the deep copy results in a completely independent object structure; changes made to the deep copy will not affect the original object and vice versa.

Thus, the correct response highlights that a shallow copy inserts references to the same nested objects, while a deep copy results in the creation of entirely new objects for each element, making them distinct from those in the original. This understanding is essential for managing mutable objects in Python, particularly when it comes to avoiding unexpected behavior when manipulating collections of objects.