Complex sentence: At the conclusion of the war, the Daleks, heavily mutated by radiation, encased themselves in protective machines and retreated into their city, while the humanoid Thals survived the fallout through the use of an anti-radiation drug and became a peaceful race of farmers.
Split into simpler sentences: At the conclusion of the war the Daleks, heavily mutated by radiation, encased themselves in protective machines and retreated into their city. The humanoid Thals survived the fallout through the use of an anti-radiation drug and became a peaceful race of farmers.