Queues - General Questions

Starting with an empty queue: enqueue(6), enqueue(3), enqueue(1), dequeue(), enqueue(1), enqueue(3), enqueue(2). Which element is at the front?

How many stacks are needed to implement a queue?

Starting with an empty queue: enqueue(3), enqueue(4), enqueue(7), dequeue(), dequeue(), enqueue(3), dequeue(). Which element is at the front?

Starting with an empty queue: enqueue(1), dequeue(), enqueue(8), dequeue(), enqueue(6), enqueue(6), enqueue(2). Which element is at the front?

Starting with an empty queue: enqueue(2), enqueue(2), dequeue(), enqueue(6), dequeue(), enqueue(1), enqueue(7). Which element is at the front?