Problem: Samurai were many of the early exchange students, not directly because they were samurai, but because many samurai were literate and well-educated scholars. Some of these exchange students started private schools for higher educations, while many samurai took pens instead of guns and became reporters and writers, setting up newspaper companies, and others entered governmental service. Some samurai became businessmen. For example, Iwasaki Yatarō, who was the great-grandson of a samurai, established Mitsubishi.
Who started Mitsubishi?
The answer is the following: Iwasaki Yatarō

Problem: Most videos enable users to leave comments, and these have attracted attention for the negative aspects of both their form and content. In 2006, Time praised Web 2.0 for enabling "community and collaboration on a scale never seen before", and added that YouTube "harnesses the stupidity of crowds as well as its wisdom. Some of the comments on YouTube make you weep for the future of humanity just for the spelling alone, never mind the obscenity and the naked hatred". The Guardian in 2009 described users' comments on YouTube as:
Most videos enable users to do what
The answer is the following: leave comments

Problem: The Sumerians developed a complex system of metrology c. 4000 BC. This advanced metrology resulted in the creation of arithmetic, geometry, and algebra. From c. 2600 BC onwards, the Sumerians wrote multiplication tables on clay tablets and dealt with geometrical exercises and division problems. The earliest traces of the Babylonian numerals also date back to this period. The period c. 2700 – 2300 BC saw the first appearance of the abacus, and a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system. The Sumerians were the first to use a place value numeral system. There is also anecdotal evidence the Sumerians may have used a type of slide rule in astronomical calculations. They were the first to find the area of a triangle and the volume of a cube.
When was the abacus first seen between?
The answer is the following: 2700 – 2300 BC

Problem: Ectosymbiosis, also referred to as exosymbiosis, is any symbiotic relationship in which the symbiont lives on the body surface of the host, including the inner surface of the digestive tract or the ducts of exocrine glands. Examples of this include ectoparasites such as lice, commensal ectosymbionts such as the barnacles that attach themselves to the jaw of baleen whales, and mutualist ectosymbionts such as cleaner fish.
Name a parasitic ectosymbiont.
The answer is the following:
lice