In 1905, Levene was appointed as head of the biochemical laboratory at the Rockefeller Institute of Medical Research. He spent the rest of his career at this institute, and it was there that he identified the components of DNA.
It also takes anywhere from 18 to 24 months to get promoted to O-2 following entry to the Army, so the effective minimum age to join the Rangers for officers is around 23 to 24 years old. Officers can then continue to apply until they are promoted to O-5.
So about 17-24 is about the average age.   The median age of Korean War veterans is estimated to be 69 years, with an estimated 336,500 under age 65, 3.25 million aged 65 to 74, and an estimated 363,600 aged 75 or older. So about 17-24 is about the average age.s such, enlisted would have an average age around 22, with NCOs averaging 27. With the introduction of US ground forces for combat, the enlisted ranks were generally filled with draftees.