Answer: The element of Logos
Explanation: Logos is one of the three Aristotle's elements of good communication, it consists on the reliability that you have as a person, due to the logic of your statements or the approach you use to share your knowledge. In this case, Dexter relies on his trainer Ken because he shows him a method to complete his task faster. Dexter respects and follows Ken's instructions because of the accuracy of his philosophy.
It is 4. because it says in the paragraph and I quote: "helium has a very low density. it is used in daily weather balloons to carry instruments that record, tempature, humidy, and pressure readings in the atmosphere.
