<span> el mecanismo es fotosíntesis </span>
The tip of the pyramid ends in a cuplike structure called the papilla.
Papilla projects into a calyx. Its surface has a sievelike appearance since it is where urine droplets pass through its small openings. Each opening represents a tubule known as the Bellini duct through which collecting tubules within the pyramid converge or meet. The muscle fibers lead from the calyx to the papilla. As the muscle fibers originating from calyx contract, urine flows through the Bellini ducts into the calyx. The urine flows through the renal pelvis and the ureter and it eventually drains down into the bladder.
<span>Of SiF4 and SiBr4, the atom SiF4 is more polar. This is because the cation of both molecules are Silicon, but the anions of each are different. In SiF4, the anion is Fluorine, which is more electronegative than the Bromine in SiBr4, which creates a larger dipole, which results in a more polar molecule.</span>
