The development of breech loading had the greatest effect on naval warfare, for the first time since the Middle Ages, altering the way weapons are mounted on warships, and therefore naval tactics, now divorced from the reliance on sails with the invention of the internal combustion. A further advance in military naval technology was the design of the submarine, and its weapon, the torpedo.

Since 1976, the multiple-choice ASVAB has been used for initial aptitude screening as well as MOS classification. The exam has changed since its inception. While some parts have remained, such as arithmetic reasoning and word knowledge, others like tool knowledge have been removed in favor of questions related to assembling objects. After nearly 20 years of research and development, a computer-adaptive version of the exam was implemented in 1996. The CAT-ASVAB is the first large-scale adaptive battery test to be administered in high-stakes environments like a Military Entrance Processing Station. The paper and pencil, or P&P version is still used at a variety of other military testing sites.
Educational Opportunities–More educational opportunities are available than ever before.  Alternatives to traditional education, such as online courses and weekend or evening programs, allow individuals to obtain higher education while working full-time.  New technology, such as live podcasts and streaming videos on demand, make it possible for people to learn at their own pace in their own place.  Education is a lifelong process.  Many people now choose to combine their education with work experience.  For instance, instead of attending a four-year college immediately after high school, some people get a two-year degree in a particular field and then enter the job force.  At some point, they may choose to complete a certificate program or a four-year degree to advance in their chosen field.  Other people choose to enter the Military to take advantage of the educational benefits and training that is provided.  There are a variety of occupations and career paths that you can pursue with different levels of education.  Do not rule out a given career field simply because you think that the educational requirements might be more than what you would like to pursue after high school.
General Science tests the ability to answer questions on a variety of science topics drawn from courses taught in most high schools. The life science items cover botany, zoology, anatomy and physiology, and ecology. The earth and space science items are based on astronomy, geology, meteorology and oceanography. The physical science items measure force and motion mechanics, energy, fluids, atomic structure and chemistry.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.

ASVAB CEP test results are sent to students’ schools so they can explore career options with counselors. The scores show how well the student did on each subject, and how they compare with others who took the test. There are three composite scores in Verbal, Math, and Science and Technical skills, and the Armed Forces Qualification Test (AFQT) score is also reported.
Battlefield commission: under certain conditions, enlisted personnel who have skills that separate them from their peers can become officers by direct commissioning of a commander so authorized to grant them. This type of commission is rarely granted and is reserved only for the most exceptional enlisted personnel; it is done on an ad hoc basis, typically only in wartime. No direct battlefield commissions have been awarded since the Vietnam War. The Navy and Air Force do not employ this commissioning path.

Another big advantage of practice tests is that they are fun. It’s fun to challenge yourself and see what you know. Instead of wondering if you are studying the right things or just wasting your valuable time, good practice tests can help you find out what you need to know while injecting your study time with excitement and competition as you try to outdo yourself each time you take a test.
In the 2000s, women can serve on U.S. combat ships, including in command roles. They are permitted to serve on submarines.[39] Women can fly military aircraft and make up 2% of all pilots in the U.S. Military. In 2003, Major Kim Campbell was awarded the Distinguished Flying Cross for landing her combat damaged A-10 Thunderbolt II with no hydraulic control and only one functional engine after being struck by hostile fire over Baghdad.