IXL is the world's most popular subscription-based learning site for K–12. Used by over 11 million students, IXL provides personalized learning in more than 8,500 topics, covering math, language arts, science, social studies, and Spanish. Interactive questions, awards, and certificates keep kids motivated as they master skills. Start studying Operating & Transfer Zones. Learn vocabulary, terms, and more with flashcards, games, and other study tools.If atoms are made up mostly of "empty space," what is in that empty space? Specifically, is there air in the empty space of an atom? The space inside the atom is just that, empty space, i.e. vacuum. Mar 25, 2020 · The water can then flow up through the xylem into the zone of less pressure. In general, bulk flow in plants is a quicker process than osmosis or diffusion, both of which involve a passive transport of materials from an area of high to low pressure. But diffusion can transfer materials only over short distances, which is a problem for tall plants.