Complex sentence: During the Russian Revolution the family had to leave Persia, and in 1923 they settled in Paris where he was educated, graduating in physics, chemistry and biology, and taking his doctorate in medicine, at the University of Paris.
Split into simpler sentences: During the Russian Revolution the family had to leave Persia, and in 1923 they settled in Paris where he was educated. He graduated in physics, chemistry and biology, and took his doctorate in medicine at the University of Paris.