Consider a massive online open courseware(MOOC) such as udemy or coursera. The MOOC is a platform for online courses where students only need a computer and internet connection to get enrolled and learn a course from any part of the world. The student just needs to login to site, and the site provides information about latest trending courses. Student can also search for a course from search catalog by providing either course name or institute name. The site displays all the courses based on the students criteria. The course display information includes all the free and paid courses with course duration. If a student selects free course, he will have to add the course to cart and proceed to checkout where the system will ask for student name, email address and a message will be sent to his email address as a confirmation that he has been enrolled in to course. If the student gets enrolled in to a paid course, the system will ask for payment through paypal or credit card. Once the student enters the details the system will send confirmation message to students email address. The student will get enrolled in to the class and on successful completion he will be awarded with a certification.

1. For the system given above you are required to make a use case diagram and a domain model.
2. Make an activity diagram for the process of enroll in to course.