Solution

A spliceosome is a large and complex molecular machine found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from snRNAs and approximately 80 proteins. The spliceosome removes introns from a transcribed pre-mRNA, a type of primary transcript. Bacteria are prokaryotes, which consist of a single cell with a simple internal structure. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Hence spliceosomes are not found in bacteria. So the correct option is 'bacteria,