Which of the following is a true statement about the water cycle? some of the water in the deepest parts of the ocean never becomes part of the water cycle. sometimes the water cycle is very fast, circulating the water in all the oceans in under 100 years. due to mixing and oceanic gyres, even very deep water is part of the water cycle. water molecules are either part of the land system of mountains, rivers, and lakes, or part of the ocean system, and do not travel from one to the other.