Natural Structures
Natural Structures: Shells, trees, skeletons, nests, etc.
Natural structures are divided in three gropus: animal, vegetable and geological.
Natural animal structures: nests, beaver dams, termite hills, coral, wasp nests, bee, hives, tunnels made by moles, mice, rabbits, birds’ eggs, tortoise shells, etc.
Natural geological structures: caves, mountains, etc.
Natural vegetable structures: tree trunks, branches, etc.