Answer:
Active transport.
Explanation:
The kidney uses active transport to move these substances from the nephron to the renal vein because these substances did not moves from the nephron bowl to the renal vein through simple diffusion so for this purpose active transport is used in which energy is spent in order to move the substances from one region to another so we can say that kidney must use active transport to move reabsorbed substances from the nephron to the renal vein.
I think that it is the bone system please tell me if right
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
