Answer:
I have never actually seen a zigzag ruler, but I would assume to make zigzag lines.
Explanation:
2D is flat and 3D is visible in 3 dimensions and looks like it is popping out.
Answer: Cross-contamination
Explanation: it is the transfer of harmful organisms from one surface to another that is often the cause. This is especially troublesome for raw, ready-to-eat foods, such as salads or other produce.