
The nephron loops of the juxtamedullary nephrons are surrounded by a looping, ladder-like blood vessel called the

The nephron loops of the juxtamedullary nephrons are surrounded by a looping, ladder-like blood vessel called the Peritubular Capillary network
This network is formed by the Efferent artiole to absorb the non waste martial which is flown out in the ultrafiltration of Glomerular capsule .
Answer:
A) Made Of Metal
Explanation:
It is a well known fact that magnets stick only to metal and the opposite side of another magnet.
There is no pigment in the brain, so it is in it's natural colour, grey.