▁meant ▁to ▁enh ance ▁the ▁student ' s ▁knowledge ▁on ▁a ▁certain ▁field ▁of ▁study . ▁M ole cular ▁evolution , ▁for ▁example , ▁is ▁a ▁limited ▁option ▁discipline ▁for ▁Bi ology ▁students . ▁Free ▁discipl ines ▁are ▁all ▁discipl ines ▁that ▁don ' t ▁fit ▁in ▁either ▁one ▁of ▁the ▁previous ▁categories . ▁L IB R AS ▁is ▁a ▁free ▁discipline ▁on ▁all ▁non - lic enti ate ▁courses . ▁ ▁E valu ation ▁ ▁The ▁fact ▁that ▁the ▁curr icul um ▁has ▁no ▁fixed ▁order ▁introdu ces ▁some ▁dis adv antages , ▁for ▁example , ▁one ▁professor ▁may ▁apply ▁harder ▁ex ams ▁than ▁the ▁others , ▁creating ▁a ▁dispar ity ▁between ▁gr ades ▁on ▁the ▁same ▁discipline . ▁Some , ▁however , ▁are ▁" un ified ", ▁meaning ▁that ▁the ▁same ▁ex ams ▁and ▁ev all u ations ▁will ▁be ▁applied ▁to ▁all ▁students , ▁prevent ing ▁that ▁dis party . ▁Ex cluding ▁Quant um ▁Physics ▁and ▁Str ucture ▁of ▁M atter , ▁all ▁Physics ▁related ▁discipl ines ▁are ▁un ified . ▁ ▁D ifferent ▁discipl ines ▁have ▁different ▁evaluation ▁systems . ▁One ▁may ▁have ▁three , ▁two , ▁one ▁or ▁no ▁ex ams ▁at ▁all ▁( in ▁this ▁case , ▁the ▁evaluation ▁is ▁made ▁via ▁a ▁project ▁developed ▁by ▁the ▁student ). ▁There ▁may ▁also ▁be ▁a ▁student ▁project ▁and ▁one ▁or ▁two ▁ex ams . ▁ ▁Stud ents ▁who ▁get ▁a ▁lower ▁than ▁C ▁grade ▁have ▁the ▁option ▁to ▁do ▁one ▁last ▁exam , ▁which ▁is ▁sometimes ▁referred ▁to