Complex sentence: Over 75,000 total US Marines fought on Iwo Jima, over 5500 Marines were killed and thousands more wounded, along with 720 Navy Corpsman and Navy Doctors being wounded or killed.
Split into simpler sentences: Over 75,000 total US Marines fought on Iwo Jima. Over 5500 Marines were killed and thousands more wounded, along with 720 Navy Corpsman and Navy Doctors being wounded or killed.