Which of the following planets can be seen as a crescent phase from Earth?

Which of the following planets can be seen as a crescent phase from Earth?
 
  a. Mercury
  b. Venus
  c. Mars
  d. Mercury and Venus
  e. All of the other choices are correct.

Question 2

Helioseismology shows that deeper layers of gas in the Sun rotate at different speeds. When different parts of an object rotate at different rates it is called
 
  a. the dynamo effect.
  b. lagging.
  c. reconnection.
  d. differential rotation.
  e. the Zeeman effect.

Question 3

The period of Jupiter's orbit around the Sun is approximately 12 years. What is the approximate distance from the Sun to Jupiter?
 
  a. 144 AU
  b. 1728 AU
  c. 42 AU
  d. 5.2 AU
  e. 2.3 AU

Question 4

________ occur about 130 km above Earth's surface near the polar regions when energy in the solar wind guided by Earth's magnetic field excites gases in the upper atmosphere.
 
  a. Coronas
  b. Flares
  c. Auroras
  d. Coronal holes
  e. Nuclear fission