An example of a grad-school level question?
A lunar eclipse occurs when the Moon passes through Earth's shadow. A lunar eclipse can only occur during a

An example of a grad-school level question?
What type of precipitation occurs when raindrops freeze as they fall?

An example of a grad-school level question?
Which gas makes up the greatest percentage of Earth's atmosphere?

An example of a grad-school level question?

Which natural event can dry out plants and cause wildfires?