Extending outwards from the core are the mantle and the crust. Earth's mantle extends to a depth of 2,890 km beneath the surface, making it the thickest layer of Earth. This layer is composed of silicate rocks that are rich in iron and magnesium relative to the overlying crust.
The Parasite: Balantidium coli. Balantidium coli is the only ciliate known to parasitize humans. Ciliates represent a phylum of protozoa characterized, in at least one stage of development, by simple or compound ciliary organelles on the surface of their membranes that are used for locomotion.
Lucentis (ranibizumab) is made from a human antibody fragment. It works by keeping new blood vessels from forming under the retina (a sensory membrane that lines the inside of the eye). In people with certain types of eye disorders, new blood vessels grow under the retina where they leak blood and fluid.