Personnel may be recruited or conscripted, depending on the system chosen by the state. Most military personnel are males; the minority proportion of female personnel varyies internationally (approximately 3% in India,[8] 10% in the UK,[9] 13% in Sweden,[10] 16% in the US,[11] and 27% in South Africa[12]). While two-thirds of states now recruit or conscript only adults, as of 2017 50 states still relied partly on children under the age of 18 (usually aged 16 or 17) to staff their armed forces.[13]
Each of the five services employs a single Senior Enlisted Advisor at departmental level. This individual is the highest ranking enlisted member within that respective service and functions as the chief advisor to the service secretary, service chief and Congress on matters concerning the enlisted force. These individuals carry responsibilities and protocol requirements equivalent to three-star general or flag officers. They are as follows:
25. Use the following passage to answer questions 25 and 26. Sarah is about to fly from New York to Los Angeles. She packs the night before and checks her list three times. Anxiety keeps her from sleeping well. The next morning, she accidentally puts salt in her coffee instead of sugar. She forgets her purse and has to go back to the house to get it. Finally, she arrives at the airport just in time to catch her flight. The flight is uneventful, and soon Sarah is landing at LAX. Her sister is waiting for her. What was the main idea of this passage?

Arguably, the greatest invention that affected not just the military, but all society, after adoption of fire, was the wheel, and its use in the construction of the chariot. There were no advances in military technology, until, from the mechanical arm action of a slinger, the Greeks, Egyptians, Romans, Persians, Chinese, etc., development the siege engines. The bow was manufactured in increasingly larger and more powerful versions, to increase both the weapon range, and armour penetration performance. These developed into the powerful composite and recurve bows, and crossbows of Ancient China. These proved particularly useful during the rise of cavalry, as horsemen encased in ever-more sophisticated armour came to dominate the battlefield.

Later this became known as military science, and later still, would adopt the scientific method approach to the conduct of military operations under the influence of the Industrial Revolution thinking. In his seminal book On War, the Prussian Major-General and leading expert on modern military strategy, Carl von Clausewitz defined military strategy as 'the employment of battles to gain the end of war'.[34] According to Clausewitz:

Examinees also receive a score on what is called the Armed Forces Qualification Test (AFQT). AFQT scores are computed using the Standard Scores from four ASVAB subtests: Arithmetic Reasoning (AR), Mathematics Knowledge (MK), Paragraph Comprehension (PC), and Word Knowledge (WK). AFQT scores are reported as percentiles between 1-99. An AFQT percentile score indicates the percentage of examinees in a reference group that scored at or below that particular score. For current AFQT scores, the reference group is a sample of 18 to 23 year old youth who took the ASVAB as part of a national norming study conducted in 1997. Thus, an AFQT score of 90 indicates that the examinee scored as well as or better than 90% of the nationally-representative sample of 18 to 23 year old youth. An AFQT score of 50 indicates that the examinee scored as well as or better than 50% of the nationally-representative sample.