2. Determine the main structural difference between a spiral
galaxy and a elliptical galaxy.

The spiral galaxy is flat in contrast with the elliptical curve. All stars rotate in a circular motion. Given that the center of our galaxy Sagittarius A is in the southern part, it is safe to say that it is in the upper part of the disk. The image below shows where we are in relation to the center of the galaxy.

Explanation:

1. law of superposition: when there are horizontal layers of rock. the layers at the top are the youngest.

2. law of uncomformity: where one layer is much younger than the previous one, therefore creating a gap in the time record.

3. inclusion: when there is a solid stone inside of another.

4. intrusion: a feature formed when a stone is filled with magma.

hope i answered your question.