One issue is to which President or Congress a particular year's deficit should be attributed. U.S. Congressional terms start on Jan. 1, Presidential terms later in January, and the fiscal year on Oct. 1, so none of them exactly match up.
These nephridia, which are called protonephridia, are branched tubules of ectodermal origin. They are closed at the internal ends by terminal cells, or solenocytes, and open to the exterior by means of excretory pores, or nephridiopores.
Nephrons are microscopic tube-like structures in the kidneys that filter the blood and cause wastes to be removed. They are the most basic structures of the kidney's anatomy, and are an integral part of the urinary system. Each kidney contains over one million of them. Nephrons are the main functional units of the kidneys. These tiny filtering units are responsible for removing harmful toxins and excess fluids from the blood, keeping it clean and maintaining its correct volume and concentration.