Complex sentence: After the industrial revolution had introduced inorganic methods, most of which were not well developed and had serious side effects, an organic movement began in the 1940s as a reaction to agriculture's growing reliance on synthetic fertilizers and pesticides.
Split into simpler sentences: After the industrial revolution had introduced inorganic methods, most of which were not well developed and had serious side effects. An organic movement began in the 1940s as a reaction to agriculture's growing reliance on synthetic fertilizers and pesticides.