Ключевые слова: 22, 22 april, bio, biology, carbon dioxide, cartography, community, concept, conceptual, conservation, continent, earth, earth day, earth hour, eco, ecological, ecology, ecosystem, element, environment, environmental, environmental pollution, environmental problems, geography, global, globe, graphic, green, international, leaf, life, map, modern, natural, nature, organic, peace, planet, planet earth, pollution, protect, protection, recycle, save, sphere, symbol, tree, typography, world, world map,