A Stack is a container that includes all the objects inserted and removed following the last-in-first-in (LIFO) principle. The Queue is also a container that includes objects (of linear collection) inserted and removed following the first-in-first-out (FIFO) principle. 

Stack in computer science is an abstract and non-primitive data type that is an ordered and linear sequence of objects. It follows the last-in-first-out (LIFO) principle, for example, stacking plates. The plates are arranged from bottom to top and taken out from the top first, and you can also add plates only on the top.

On the other hand, Queue is a linear structure following an order to perform the operations, and it follows the first-in-first-out principle. For example, a queue of customers in a billing counter and the first one in the line will be billed first.

Both Stack and Queue are non-primitive data structures, but they differ in the principles they use to perform operations. The primary difference between them is that Stack uses the last-in-first-out (LIFO) principle to access and add the data elements. Queue uses the first-in-first-out (FIFO) principle to add and access data elements.

Yes, you will get a certificate of completion for Stacks and Queues after completing all the modules and cracking the assessment. The assessment tests your knowledge of the subject and badges your skills.
 

It is an entirely free course from Great Learning Academy. Anyone interested in learning the basics of Stacks and Queues can get started with this course.