Short answers, pulled from the story.
The Second Continental Congress passed a resolution to raise two battalions of marines on the 10th of November 1775. Captain Samuel Nicholas received his commission from John Adams to lead these new troops in Philadelphia.
Six hundred thousand Americans served in the U.S. Marine Corps during World War II and fought battles at Guadalcanal, Bougainville, Tarawa, Guam, Tinian, Saipan, Peleliu, and Okinawa. The Battle of Iwo Jima began on the 19th of February 1945 and remains the most famous engagement of the war with nearly 87,000 marines as casualties overall including nearly 20,000 killed.
President Harry Truman wrote a letter dated the 29th of August 1950 calling the Marine Corps the Navy's police force which caused outrage among Congressmen and Marine organizations. The Douglas-Mansfield Act passed in 1952 gave the commandant an equal voice with the Joint Chiefs of Staff and established the structure of three active divisions and air wings that remain today.
Four principal bases host operating forces including Camp Pendleton Camp Lejeune and Camp Butler in Okinawa Japan. Camp Pendleton home to I Marine Expeditionary Force sits on the West Coast while Camp Lejeune home to II Marine Expeditionary Force is on the East Coast and Twentynine Palms California hosts the largest combined-arms live-fire training center.
Opha May Johnson became the first woman to enlist in the Marines Reserve in 1918 during World War I. Three hundred five women enlisted from then until the end of that war and women make up 7.8% of personnel as of December 2020.