For our Biology class, our teacher, Male, gave us a worksheet with some questions for us to answer to revise the topic of excretion and kidneys.

1) a) Define the terms excretion and egestion

• Excretion as removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements.
• Egestion as the passing out of food that has not been digested or absorbed, as faeces, through the anus

1) b) The kidney is an excretory organ. It produces urine that contains urea. State where in the body urea is formed and what is formed from.

Urea is formed in the liver from excess amino acids.