Differentiate between:

Renal cortex and Renal medulla (location and appearance) 

Differentiate between:

Renal pelvis and renal papilla (structure)

Differentiate between:

Urea and urine

Differentiate between: 

Excretion and secretion (utility)

Give reason/explain:

Excretion is a necessary process of our body. 

Give reason/explain:

If we donate one kidney to a needy patient it would not cause any harm to us.

Give reason/explain:

We urinate fewer times in summer than in winter and the urine passed is generally thicker.