In each pair, click on the better introduction, the one that, in addition to engaging the reader's attention, clearly states a t
hesis (a) In the eighteenth century, an English clockmaker named John Harrison received a prize for a clever invention that allowed sailors to calculate longitude. He created a clock that required no pendulum and contained different kinds of metal. This clock worked on board a ship that was at sea, and it worked in many different temperatures and climates.
(b) Until the eighteenth century, sailors at sea had no way of calculating the longitude of their ships with any accuracy. As a result, countless sailors died when they lost track of their position and their ships ran aground. Great scientific minds tried to solve the problem of longitude without success, but it was a self-taught English clockmaker, John Harrison, who invented a device that worked. Harrison's invention must rank as one of the greatest contributions to the field of navigation.
It would depend because being loyal to your country benefits more people but being loyal to your friend is more special because obviously they are your friend, you have known them and like them. But again, it would depend on the situation.
