What harms the respiratory and circulatory systems?
oil rain sulfur cars tires coal tar bicycles
A B C D E F G H
Cars are a significant source of air pollution.
Cars harm the respiratory and circulatory systems.
What harms the respiratory and circulatory systems? (A) oil (B) rain (C) sulfur (D) cars (E) tires (F) coal (G) tar (H) bicycles