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 understanding that can be developed in a variety of ways. Comparing sounds is the easiest task for developing phonemic awareness. Sound sorts can be introduced very early on and develop strategically throughout primary learning. An ability to sort sounds is essential for early reading because sound manipulation is a stepping stone to word study and decoding ability. For some students a direct instructional approach is not necessary in the development of sound study and sorting. Other children who have had less exposure or lack the understanding of sounds and their manipulability may need further instruction to develop their ability. Teachers