Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
There are many blood vessels in the kidneys ( Figure above ). The kidneys remove urea and other wastes from the blood through tiny filtering units called nephrons. Nephrons ( Figure below ) are tiny, tube-shaped structures found inside each kidney. Each kidney has up to a million nephrons. Each nephron collects a small amount of fluid and waste from a small group of capillaries.


Question: What are the tiny, tube-shaped structures found inside a kidney called?
nephrons
Nephrons.