Which one of the following correctly explains the function of a specific part of the human nephron?

$I.$ Ureter,$II.$ Renal pelvis,$III.$ Calyx,$IV.$ Urinary bladder,$V.$ Urethra. Choose the correct sequence of the urine route to the outside.

Identify the odd one out.

In the mammalian kidney,the loop of Henle is present in:

Read the following four statements $(A-D)$ and select the correct ones:
$(A)$ The medulla of the kidney is divided into a few conical masses projecting into the calyces.
$(B)$ The cortex of the kidney extends in between the medullary pyramids as renal columns called columns of Bertini.
$(C)$ The kidneys are situated in the ventral part of the thoracic region in the human body.
$(D)$ Each kidney of an adult human measures $10-12 \ cm$ in length,$5-7 \ cm$ in width,$2-3 \ cm$ in thickness,with an average weight of $120-170 \ gm$.

The functional and structural unit of the kidney is ........ .