Sciences Division
The sciences division is the corps of officers within Starfleet who specialize in both scientific and medical research and control functions on starbases, aboard starships, and at Starfleet Command. Members of the sciences division may specialize in sensors, research, theoretical and physical laboratory work, biological studies, and also as technicians, medics, and surgeons.
Officers who belong to the sciences division sometimes wear the division color of another department than that which they specialize in, if said science officer were to become a department head, they might wear the colors of command division, or if they have a dual specialty is an operations division department, an alternate color might be worn.
By the 2270s, new uniforms showed different division colors, the sciences division was signified by two differing colors. Science research and technical staff wore orange behind their Starfleet badge, on uniform bands, accessories, and epaulets. Medical crew now wore green badge backings and accessories.
The sciences division was changed again with the 2280s uniforms, with green continuing to represent medical personnel, but science and technical staff now wore gray colors (which was a style shared by services personnel of operations division). The insignia used gave the officer the option of wearing command division white uniform insignia, with another department color like sciences' banded across, or the opposite, with department color insignia (green or grey, in this case) with command white banded across.
By the uniforms used from 2350s onward, blue had again become the sciences division color, and this has continued through several uniform styles.
The second variant of the 2371 uniform, whilst still referred to as blue, is strictly a shade of green, in this case jungle green. The color would later be applied to the 2373 uniforms as well.