Complex sentence: Chylomicrons are formed in the endoplasmic reticulum in the absorptive cells of small intestines, to be specific the mucosal cells within the villi of the duodenum.
Split into simpler sentences: Chylomicrons are formed in the endoplasmic reticulum in the absorptive cells of small intestines. To be specific, the mucosal cells within the villi of the duodenum.