Sample 1 has bands of light and dark crystals. Sample 2 has pink, gray, and white crystals grown together. Sample 3 is made up of one huge, pale pink crystal. Sample 4 is made up of layers of sand grains cemented together.
I gave my students this multiple choice question: A student made observations of four rock samples. Which of these observations most likely describes a sedimentary rock?

Only one answer is correct among these 4 choices:
- Sample 1 has bands of light and dark crystals.
- Sample 2 has pink, gray, and white crystals grown together.
- Sample 3 is made up of one huge, pale pink crystal.
- Sample 4 is made up of layers of sand grains cemented together.

Could you tell me which one is correct?

Sample 4 is made up of layers of sand grains cemented together.