An astronomer is studying two stars that are the same distance from Earth. Star X appears brighter than star Y. Which statement best explains this observation? OPTIONS:
- Star X is larger than star Y.
- Star Y is larger than star X.
- Star X reflects the Sun’s light better than star Y.
- Star Y reflects the Sun’s light better than star X.
A: Star X is larger than star Y.

A turtle eating worms is an example of OPTIONS:
- breathing
- reproducing
- eliminating waste
- taking in nutrients
A: taking in nutrients

What do earthquakes tell scientists about the history of the planet? OPTIONS:
- Earth’s climate is constantly changing.
- The continents of Earth are continually moving.
- Dinosaurs became extinct about 65 million years ago.
- The oceans are much deeper today than millions years ago.
A: The continents of Earth are continually moving.

The noble gases, helium, neon, argon, krypton, xenon, and radon, rarely react with other elements because they OPTIONS:
- are low-density gases.
- are not abundant on Earth.
- have complete outermost energy levels.
- have two electrons in their outermost energy level.
A:
have complete outermost energy levels.