Choose the statement that is true. Exoplanets can be observed by the reflected light they give off from their star much the same way we can observe Mars, Venus and Jupiter.
It is estimated that 50% of the estimated 100 billion stars in the Milky Way galaxy have 5 or more planets.
The radial transit method of detecting star wobble registers the amount of red shift and blue shift and blue shift detectable in the star's movement as it moves away from us or towards us.
The habitable zone is where stars and planets are not threatened by either supernovas exploding or from being swallowed by black holes.