12. Early one morning students observed the moon as it appeared from Earth. Which diagram shows the correct relative positions of the sun, the moon, and Earth when the moon was in the observed phase?

I'm unable to see images or diagrams. However, I can help you understand how to determine the correct relative positions of the Sun, Moon, and Earth based on the phase of the Moon you observed.

1. **New Moon**: The Moon is between the Earth and the Sun, and the illuminated side is facing away from Earth.
2. **Waxing Crescent**: The Moon is slightly east of the Sun (from Earth's perspective), with a sliver of light visible.
3. **First Quarter**: The Moon is at a right angle to the line between the Earth and the Sun. Half of the Moon is illuminated.
4. **Waxing Gibbous**: The Moon is still moving away from the Sun, but more than half is illuminated.
5. **Full Moon**: The Earth is between the Moon and the Sun, with the entire face of the Moon illuminated.
6. **Waning Gibbous**: The Moon is past full, moving towards the last quarter, but still more than half is lit.
7. **Last Quarter**: Like the first quarter but on the opposite side, half of the Moon is illuminated.
8. **Waning Crescent**: The Moon approaches a new phase, with a small sliver of illumination left.

If you can describe the phase of the Moon that the students observed, I can help you determine which diagram (A, B, C, or D) is correct.