Out of these multiple choice, what’s the correct answer?

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?

A15 ohm resistor and a 25 ohm resistor are connected in parallel to a 60 volt battery. what is the power used by each device

The height of the empire state building is 318 m if a stone is dropped from the top of the building what is the stones velocity just before it strikes the ground