Nephrons in birds, mammals, and reptiles are all extremely similar, more so than other structures in the bodies of different species, solidifying the relatedness through similarity.
Explanation:
Birds can be said to have "mammal-like" nephrons from the number of loops and overall structure of their kidneys, which, although they look very different, serve the same purpose and do it in largely the same way. Reptiles also have mammal-like nephrons, and it can be assumed that this evolutionary trait was kept because the specific structure of the nephrons is generally the most efficient.
The fluid inside of the Extracellular Matrix is Extracellular Fluid. Extracellular Fluid is also called ECF. ECF is mostly tissue fluid. It is also made up of a large amount of intravascular fluid. The remaining smaller amount of ECF is transcellular fluid.
