The primary or main excretory organ in humans is:

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 $120-170 \ gm$.

In which of the following is the minimum content of urea present?

Bowman's capsule is lined by ........

Distinguish between: Juxtamedullary and Cortical nephrons.

Select the correct sequence of blood flow in the kidney.