The following "Courses ERD" represents courses and sections as offered at UNB. This ERD

applies to Questions $2$ to $7.$

UNB offers courses in a wide variety of subject areas, including the subject area codes CS$,$

MATH, and ENGL, just to name a few. Those three codes represent the subject areas named

Computer Science, Mathematics, and English, respectively.

Each course in UNB's Undergraduate Calendar is in exactly one subject area and has a course

title $($e$.$g$.$ 'Introduction to Databases'$).$

A section is an offering of a course that takes place during a specific academic term, such as

Winter $2022($represented in this database by the code $\text{'}$W$2022\text{'}).$

$(2$ marks$)($Weak entities$)$

$($a$)$ Name each weak entity in the Courses ERD $($if there are any$)$:

$($b$)$ Explain the reasons for your answer to part $($a$)$: