Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. A major risk factor is increased pressure in the eye. The disorders can be roughly divided into two main categories:  open-angle  and  closed-angle  (or  angle closure ) glaucoma.laucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. A major risk factor is increased pressure in the eye. The disorders can be roughly divided into two main categories:  open-angle  and  closed-angle  (or  angle closure ) glaucoma.
Q: A geochemical cycle that cycles material by mantle convection, subduction, and seafloor spreading is A: A geochemical cycle that cycles material by mantle convection, subduction, and seafloor spreading is TECTONIC. Weegy: erosion. The rock cycle includes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes.
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii.he theory predicts mushroom mantle plumes of about 2000 km diameter with a critical time of about 830 Myr for a core mantle heat flux of 20 mW/m 2, while the cycle time is about 2 Gyr. The number of mantle plumes is predicted to be about 17.