Available choices: a). energy usage; b). Greenhouse gasses; c). acid rain; d). harmful substances; e). Greenhouse gases; f). temperature; g). prolactin release; h). storms;
Given those answer options, answer the question: Fact 1: Riding a bike does not cause pollution. Fact 2: City employees use bicycles on the job to save energy and reduce air pollution. Given the two facts above, riding a bike reduces what?
A:
a).