Some conditions can cause the absence of OAE's. These include: cysts, external otitis (swimmer's ear for example), stenosis, or abnormal middle ear pressure, a perforated ear drum, otosclerosis, cholesteatoma.
The Gulf of Mexico (Spanish: Golfo de MÃ©xico) is an ocean basin largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba.
The Gulf of Mexico is an example of an inactive ocean basin where the main change that happens is the slow depositing of sand and sediment. Active ocean basins undergo change mainly due to plate tectonics.