Complex sentence: Meanwhile, tiberium has been ravaging the world for 35 years and has grown in many varieties, mutating flora and fauna and forcing humans to move to the polar regions, where the spread of tiberium is slowed by cold, arid conditions.
Split into simpler sentences: Meanwhile, tiberium has been ravaging the world for 35 years and has evolved into many varieties. It has mutated flora and fauna and forced humans to move to the polar regions, where the spread of tiberium is slowed by the cold, arid conditions.