This question was attempted by many candidates and their performance was poor.  In part (a) many candidates failed to define the term external respiration.  Few candidates wrongly defined external respiration as outer the body or a process in which an organism breathes in oxygen and gives out carbon dioxide.  In part (b) candidates correctly listed systems of the human body.  In part (c) many candidates could not correctly explain the principle of lever system in relation to the elbow joint.  Some wrote muscle of lower and upper arm that contract being pulley while load is effort or the elbow joint is power while the object held in the hand is pivot.
However the expected answers were as follows:                                                   
9(a)      EXTERNAL RESPIRATION
            This is the exchange of gases between the blood and the lungs/alveoli
                                                                                                                       
   (b)     SYSTEMS OF THE BODY

• skeletal system
• muscular system
• circulatory system
• respiratory system
• digestive system
• endocrine system
• reproductive system
• excretory system
• nervous system

  (c)      PRINCIPLE OF LEVER IN RELATION TO THE ELBOW JOINT

• the insertion of the triceps/biceps muscles supply the effort/power
• an object held in the hand acts as the load
• the elbow joint is the fulcrum/pivot