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.
Polyurethane is a synthetic material that is used in various applications in nearly every field imaginable. It is renowned for its durability and flexibility and can be produced in a number of different forms based on what it will be used for. Everything from airplane wings to tires can be made with polyurethane.