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: CAPILLARIES
Explanation: Gas exchange is the delivery of oxygen from the lungs to the blood stream, and the elimination of carbon dioxide from the blood stream to the lungs. It occurs in the lungs between the alveoli and a network of tiny blood vessel is called capillaries, which are located in the walls of the alveoli.
There are several different processes, including glycolysis and the Calvin Cycle, but the umbrella term for getting energy from glucose is cellular respiration.
