As of the time of the publication of the textbook, how many planet candidates have been discovered using the transit method?
A) a few thousand B) tens of thousands C) a few hundred D) about 10
Question 2
The four fundamental forces that operate in the universe today are ________.
A) strong force, weak force, electromagnetic force, gravity
B) nuclear force, electromagnetic force, gravity, tidal force
C) nuclear force, gravity, electric force, magnetic force
D) strong force, weak force, electric force, magnetic force