I've been trying to research this area but there doesn't seem to be much out there. Does any one know of any evidence or theory showing that quarks and leptons are or are not fundamental? I have heard of String Theory but does string theory actually suggest that quarks and leptons are made up of strings or is there an intermediate particle between strings and quarks and leptons? I've also come across a hypothesis called the MATPELUKA hypothesis. But I can't find any info on it. [Part (e) of this Document] Has any one else heard of this?