The porcelain layer is attached to the metal and makes the crown look like a regular tooth. In comparison, the all-porcelain or all-ceramic crown does not have the layer of metal as part of the crown. The porcelain itself is what goes onto your tooth.
Quick Answer. An abyssal plain is a deep undersea area created by sediments overlaying a rocky crust, and they are the flattest places on Earth. Abyssal plains cover one-third of the Earth's surface, as much as all land above water, and they sit near continental borders and underwater mountain ranges.
The abyssal zone or abyssopelagic is a layer of the pelagic zone of the ocean. Abyss derives from the Greek word á¼Î²ÏÏÏÎ¿Ï, meaning bottomless. At depths of 4,000 to 6,000 metres (13,000 to 20,000 ft), this zone remains in perpetual darkness and never receives daylight. These regions are also characterised by continuous cold and lack of nutrients.The abyssal zone has temperatures around 2 to 3 Â°C (36 to 37 Â°F) through the large majority of its mass. It is the deeper part of the midnight zone which starts in the bathypelagic waters above.