North-zenith-south line which divides the sky into two halves

A starburst galaxy gets this name because

A) it contains far more x-ray bursters than our Milky Way Galaxy. B) it has many stars bursting out of its disk toward intergalactic space. C) it is forming stars so fast that the starburst phase of life must be temporary. D) it contains so many stars that the galaxy's gravity cannot retain them in their orbits.

Match the words in the left-hand column to the appropriate blanks in the sentences in the right-hand column. Use each word only once.

Saturn, Earth, Mars, Venus, Uranus, Mercury, Jupiter, Neptune

1. ____________ has a rotational axis that is tilted so much it lies nearly in the plane of its orbit.

2. ____________ is the planet with the highest average surface temperature.

3. The planet that orbits closest to the Sun is __________.

4. The only rocky planet to have more than one moon is ___________.

5. ___________ is the jovian planet that orbits closest to the Sun.

6. Most of the surface of _________ is covered with liquid water.

7. ___________ is about 30 times as far from the Sun as our own planet.

8. The planet with the lowest average density is ___________.

As a particle travels faster, its de Broglie wavelength

A) increases. B) decreases. C) remains constant. D) could be any of the given answers; it depends on other factors.

Knowing that the atomic number of neon is greater than that of helium, at the same temperature and pressure, how does the speed of sound in helium gas compare to the speed of sound in neon gas?

A) greater in neon than in helium B) greater in helium than in neon C) the same in both gases D) depends on the frequency of the sound generated