Ключевые слова: activity, bicycle, bicyclist, bike, biker, biking, bus, car, carbon, change, conservation, cycle, cyclist, day, eco, ecological, ecology, environment, environmental, exercise, free, health, healthy, hobby, illustration, lifestyle, metro, monoxide, polution, protect, protection, public, question, recreation, recycle, relaxation, reuse, ride, road, sign, speed, sport, subway, train, transport, transportation, travel, vehicle, walk,