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.
The maximum enlistment age is 35. A U.S. Army website that publishes recruitment data indicates that the 20.7-year average recruitment age for active duty in 2013 is actually lower than it has been in the past 13 years.In 2007, the average age of 21.7 and in 2010 it was 21.4, according to the site. A. More than half of new enlistees in the U.S. Army are age 20 or older, a sharp rise from two decades ago, when older recruits made up just 35 percent of total Army enlistments, according to USA Today and the results of a newly released RAND Corp. study.