Definition: A peatland whose development is mostly independent of basins or topographical features where water collects; it simply covers the landscape like a blanket. Peat develops due to a continuous supply of water from rainfall, maintaining waterlogged conditions on the ground. Blanket bogs are ombrotrophic or rain fed, and as a result their pH lies between 3.5 and 4.2.
Definition: Because of the difference in refractive index between air and water (or corneal tissue), a curved cornea is an image-forming lens in its own right. Its focal length is determined by the radius of curvature of the cornea. Many corneal eyes (eg: in land vertebrates) also have lenses, but the lens is flattened and weakened compared with an aquatic lens; most of the refractive power is provided by the cornea. Corneal eyes cannot focus in aquatic habitat.