The kidneys are made up of tiny tubular units called:

1. Glomerulus
2. Nephrons
3. Capillaries
4. Neurons

Besides water, the urine mainly contains:

1. Urea
2. Nitric acid
3. Glucose
4. Bile pigments

Filtration of excretory wastes from the blood occurs in:

1. Collecting tubule
2. Ureter
3. Urinary bladder
4. Nephrons

The process of the breakdown of excessive amino acids occurs in :

1. Kidney
2. Liver
3. Small intestine
4. Lung