Fact 1: Riding a bike does not cause pollution. Fact 2: Air pollution Air pollution is a major threat to health. Given the two facts above, riding a bike does not cause what?

(a). Greenhouse gasses;
(b). forward motion;
(c). harmful substances;
(d). wear on tires;
(e). Greenhouse gases;
(f). major threat to health;
(g). contamination;
(h). sore bottom;
Answer:
(f).