Insertion and deletion complexities for a linked list and array

Question

I have the following table that compares different operation complexities for a linked list and array:

                        Linked List |   Array   |   Dynamic Array
Deletion at ending      O(n)        |   O(1)    |   O(n)
Insertion in middle     O(n)        |   O(n)    |   O(n)
Deletion in middle      O(n)        |   O(n)    |   O(n)

Can anyone please explain why:

1. Deletion for Dynamic Array is O(n)?
2. Insertion and deletion in middle for all data structures is O(n)?

Thanks