Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

Input: Consider Input: Paragraph- Sent 1: During this time, Alexander adopted some elements of Persian dress and customs at his court, notably the custom of proskynesis, either a symbolic kissing of the hand, or prostration on the ground, that Persians showed to their social superiors.
Sent 2: The Greeks regarded the gesture as the province of deities and believed that Alexander meant to deify himself by requiring it.
Sent 3: This cost him the sympathies of many of his countrymen, and he eventually abandoned it.
Sent 4: A plot against his life was revealed, and one of his officers, Philotas, was executed for failing to alert Alexander.
Sent 5: The death of the son necessitated the death of the father, and thus Parmenion, who had been charged with guarding the treasury at Ecbatana, was assassinated at Alexander's command, to prevent attempts at vengeance.
Sent 6: Most infamously, Alexander personally killed the man who had saved his life at Granicus, Cleitus the Black, during a violent drunken altercation at Maracanda (modern day Samarkand in Uzbekistan), in which Cleitus accused Alexander of several judgemental mistakes and most especially, of having forgotten the Macedonian ways in favour of a corrupt oriental lifestyle.
Sent 7: Later, in the Central Asian campaign, a second plot against his life was revealed, this one instigated by his own royal pages.
Sent 8: His official historian, Callisthenes of Olynthus, was implicated in the plot; however, historians have yet to reach a consensus regarding this involvement.
Sent 9: Callisthenes had fallen out of favor by leading the opposition to the attempt to introduce proskynesis.
Question: Why did Parmenion have to die?.

Output: The death of the son necessitated the death of the father.

Input: Consider Input: Paragraph- Sent 1: As Philip marched south, his opponents blocked him near Chaeronea, Boeotia.
Sent 2: During the ensuing Battle of Chaeronea, Philip commanded the right wing and Alexander the left, accompanied by a group of Philip's trusted generals.
Sent 3: According to the ancient sources, the two sides fought bitterly for some time.
Sent 4: Philip deliberately commanded his troops to retreat, counting on the untested Athenian hoplites to follow, thus breaking their line.
Sent 5: Alexander was the first to break the Theban lines, followed by Philip's generals.
Sent 6: Having damaged the enemy's cohesion, Philip ordered his troops to press forward and quickly routed them.
Sent 7: With the Athenians lost, the Thebans were surrounded.
Sent 8: Left to fight alone, they were defeated.
Sent 9: After the victory at Chaeronea, Philip and Alexander marched unopposed into the Peloponnese, welcomed by all cities; however, when they reached Sparta, they were refused, but did not resort to war.
Sent 10: At Corinth, Philip established a "Hellenic Alliance" (modeled on the old anti-Persian alliance of the Greco-Persian Wars), which included most Greek city-states except Sparta.
Sent 11: Philip was then named Hegemon (often translated as "Supreme Commander") of this league (known by modern scholars as the League of Corinth), and announced his plans to attack the Persian Empire.
Question: Why was Sparta not part of the "Hellenic Alliance"?.

Output: It did not welcome Philip.

Input: Consider Input: Paragraph- Sent 1: His famous series of sixteen great designs for the Apocalypse is dated 1498, as is his engraving of St. Michael Fighting the Dragon.
Sent 2: He made the first seven scenes of the Great Passion in the same year, and a little later, a series of eleven on the Holy Family and saints.
Sent 3: The Seven Sorrows Polyptych, commissioned by Frederick III of Saxony in 1496, was executed by Durer and his assistants c.
Sent 4: Around 1503-1505 he produced the first seventeen of a set illustrating the Life of the Virgin, which he did not finish for some years.
Sent 5: Neither these, nor the Great Passion, were published as sets until several years later, but prints were sold individually in considerable numbers.
Sent 6: During the same period Durer trained himself in the difficult art of using the burin to make engravings.
Sent 7: It is possible he had begun learning this skill during his early training with his father, as it was also an essential skill of the goldsmith.
Sent 8: In 1496 he executed the Prodigal Son, which the Italian Renaissance art historian Giorgio Vasari singled out for praise some decades later, noting its Germanic quality.
Sent 9: He was soon producing some spectacular and original images, notably Nemesis (1502), The Sea Monster (1498), and Saint Eustace (c.
Sent 10: 1501), with a highly detailed landscape background and animals.
Sent 11: His landscapes of this period, such as Pond in the Woods and Willow Mill, are quite different from his earlier watercolours.
Sent 12: There is a much greater emphasis on capturing atmosphere, rather than depicting topography.
Sent 13: He made a number of Madonnas, single religious figures, and small scenes with comic peasant figures.
Sent 14: Prints are highly portable and these works made Durer famous throughout the main artistic centres of Europe within a very few years.
Question: What skill did Durer possibly learn during his early training with his father?.
Output: The skill of using the burin to make engravings.