Answer: Air pollution is responsible for seven million deaths each year in the US
Explanation: https://www.who.int/health-topics/air-pollution#:~:text=The%20combined%20effects%20of%20ambient,cancer%20and%20acute%20respiratory%20infections.
Answer:a stationary front.
Explanation:
they allow repeated thunderstorms to move across the same area.
Nalah could use only 1 rat and test it multiple times.