Complex sentence: Returning to BARC, he served in many positions, heading the Immunology Section and the Cell Biology Division as well as serving as the associate director of Bioscience Group and became the director of the Bio-Medical Group in 2006, with the responsibility of six divisions.
Split into simpler sentences: Returning to BARC, he served in many positions, heading the Immunology Section and the Cell Biology Division and serving as the associate director of the Bioscience Group. He became director of the Bio-Medical Group in 2006, with the responsibility of six divisions.