Which of the following are true?

I$)$ Space requirements of doubly linked list implementation are not more than singly linked list.

II$)$ Inserting a node to a given position by doubly linked list is more simplified than singly linked list.

III$)$ Deleting a node to a given position by doubly linked list is not more simplified than singly linked list.

Iv$)$ It is more conveniant to traverse the list backwards by doubly linked list than by singly$$linked$$list$.$