Answer:
client, server
Step-by-step explanation:
A very important model in computer science is the client-server model. This model presents and explains a relationship between communicating devices in which one, called the client, makes a request for a service or resource to the other one, called the server. In other words, when a device A communicating with device B, requests a service from B, device A is said to be the client while the other device, B, is the server. A client makes a request, the server handles, interprets and responds to the request.
So, when registering online for your classes, the computer and web browser you are using is making a request (requesting a service) from the university's computer. Therefore, the computer and web browser acts a client while the university's computer acts as a server since it handles the requests from the student's computer web browser.