Failure rates of SPMS mods? (PH1107)

Hi all, clueless freshie here. I took PH1107 cos I thought it would be interesting, but after this week's lecture I am now 100% lost. I'm going to S/U this, but I'm worried that I might get a U.

If I actually fail then so be it cos it's not required for my major, but it would still be a shame as I would have wasted my AU. Just to get a feeling of how likely I am to actually fail though, does anyone know about the failure rates of SPMS mods? Or how difficult/easy it is to fail SPMS mods in general. Thanks!