Complex sentence: Betty Brosmer is an American model who was known as the "the first supermodel", and highest paid pin-up girl in the U.S. in the 1950's, subsequently had a long career in the fitness and bodybuilding movements.
Split into simpler sentences: Betty Brosmer is an American model who was known as the "the first supermodel", and highest paid pin-up girl in the U.S. in the 1950's. She subsequently had a long career in the fitness and bodybuilding movements.