A pulley system having 5 pulleys is used to raise a 450N load. Find the mechanical advantage and hence the effort if the efficiency is 75%

it's c (engineer's do their work with mechanical stuff not on any living being)

answer seismograph;

alchemy hadn't scientific methods of study, appeal to mysticism and fantasy, the knowledge of chemistry and physics were modest at that time.

alchemy was - but as new rules were discovered it either changed into chemistry or it became "unscientific".