Renal agenesis. Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop.
Polycrystalline cells are composed of multiple silicon crystals, which is a cheaper way to manufacture solar modules. Put simply, these cells are easier for a factory to produce, so they are less expensive. Polycrystalline cells are made by several methods, but most commonly with a cast of molten silicon.
1 Polyurethane, a polymer used in manufacture of hard-plastic objects. 2  Polyester, a category of natural and synthetic polymers. 3  Polystyrene, aromatic polymer made from the aromatic monomer styrene.  Polypropylene, a thermoplastic polymer used in a wide variety of applications.