Derailleur gears by 13 drive-train. Most road bicycles have two chainrings, and touring bicycles commonly have three. The rear derailleur serves double duty: moving the chain between rear sprockets and taking up chain slack caused by moving to a smaller sprocket at the rear or a smaller chainring by the front derailleur. In order to accomplish this second task, it is positioned in the path of the bottom, slack portion of chain. Sometimes the rear-derailleurs are re-purposed as chain tensioners for single-speed bicycles that cannot adjust chain tension by a different method. Although variations exist, as noted below, most rear derailleurs have
Word sort be introduced at a very early stage and develop with a child’s individual ability. Sorting pictures or oral vocabulary is a manipulation of sounds, and this manipulation increases awareness. A simple introductory sort is by initial sound and this can develop to ending sound, vowel sounds, and word families sorts. The root of importance is student motivation and involvement in the sort. By “setting the scene with sounds," sorts may include concrete materials and pictures linked to learner interest. Phonemic awareness, not phonics, is the understanding that our spoken sounds work together to make words. This is a very early