The cell nucleus is one of the largest organelles found in cells and also plays an important biological role. It composes about 10% of the total volume of the cell and is found near the center of eukaryotic cells. Its importance lies in its function as a storage site for DNA, our genetic material.
A monorail is a railway in which the track consists of a single rail. The term is also used to describe the beam of the system, or the vehicles traveling on such a beam or track.
Train tracks usually consist of two, three or four or five rails, with a limited number of monorails and maglev guideways in the mix. The word 'train' comes from the Old French trahiner, from the Latin trahere 'pull, draw'. There are various types of trains that are designed for particular purposes.