before you enrol in a 100 level unit in second year, make sure you take into consideration the number of credit points you need to complete from that level in order to complete your degree. For instance, you may need a minimum of 32 credit points in 200 level or above and that may be comprised of a lot of electives, and so you have to make sure that if you do that 100 level unit, that you still complete the sufficient number of 200, 300 and 400 (if your degree is 4 years)