Regulation of iron absorption and transport. Iron for use in synthesis of heme, iron-sulfur centers and other non-heme iron proteins is obtained from the diet and via release of recycled iron from macrophages of the reticuloendothelial system that ingest old and damaged erythrocytes (red blood cells).
Four-stroke oil is more like the oil used in cars but both 2-stroke and 4-stroke oil serve the same purpose - to keep the engine lubricated. Four-stroke dirt bike oil comes in a variety of weights like 10w-40, 20w-50 and so on. It is not mixed with gas.
Our Experience Teaching Kids to Ride a Dirt Bike. We first bought a 50cc dirt bike. If youâll be buying a 50cc dirt bike, then definitely read my tips on the best 50cc dirt bikes on the market. My 6 and 8-year-old boys were very excited about riding, but they were also very intimidated by the loud, powerful, heavy bike (to them).