The Group 4: Experimental sciences subjects of the International Baccalaureate Diploma Programme comprise the main scientific emphasis of this internationally recognized high school programme. They consist of seven courses, five of which are offered at both the Standard Level (SL) and Higher Level (HL): Chemistry, Biology, Physics, Design Technology, and, as of August 2012, Computer Science (previously a group 5 elective course) is offered as part of the Group 4 subjects. There are also two SL only courses: a transdisciplinary course, Environmental Systems and Societies, that satisfies Diploma requirements for Groups 3 and 4, and Sports, Exercise and Health Science (previously, for last examinations in 2013, a pilot subject). Astronomy also exists as a school-based syllabus. Students taking two or more Group 4 subjects may combine any of the aforementioned.