Lead.
"Due to insufficient water treatment, lead leached from water pipes into the drinking water, exposing over 100,000 residents to elevated lead levels."
Answer:
2. The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock
Explanation:
The order is most plausible when considering the "big picture" of the emergence of life-forms dating back to old and previous era of Earth's history.