What is a detail from the article "the circuit" that provides the best example of the central idea?

pretty sure 1.someone's coat was found in the lobby.  

1: indirect

2: indirect

3: direct

4: indirect

5: direct

explanation:

the gas pressure p, gas volume v, and gas temperature t are given in the formula:   pv=nrt,

r is the gas constant, and n is the number of gas moles.

if the container is cooled and remains under atmospheric pressure, where r is a constant that does not change, the volume of the container remains the same, the conclusion is drawn that, with all other values ​​unchanged, the number of gas moles n, is decreases.

the right answer is a.