The oesophagus or food pipe is part of the digestive system. It is also sometimes called the gullet. It is the tube that carries food from your mouth to your stomach. It is about 26cm (10.5 inches) long in adults.
Benzo[a]pyrene is a polycyclic aromatic hydrocarbon found in coal tar with the formula C 20 H 12. Its metabolites are mutagenic and highly carcinogenic, and it is listed as a Group 1 carcinogen by the IARC.The compound is one of the benzopyrenes, formed by a benzene ring fused to pyrene, and is the result of incomplete combustion at temperatures between 300 Â°C (572 Â°F) and 600 Â°C (1,112 Â°F).roperly speaking, benzo[ a ]pyrene is a procarcinogen, meaning that the mechanism of carcinogenesis of benzo[ a ]pyrene depends on enzymatic metabolism of benzo[ a ]pyrene to the ultimate mutagen, benzo[ a ]pyrene diol epoxide, pictured above at right.
A planetary nebula, abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The word nebula is Latin for mist or cloud, and the term planetary nebula is a misnomer that originated in the 1780s with astronomer William Herschel because, when viewed through his telescope, these objects resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and