1. Your answer: c - retina (0 points) Hard luck. Remember the lens focuses light on the retina. 2. Your answer: a - iris (1 point) Well done! The iris narrows in bright light to protect the retina and widens to let in enough light in dim conditions. 3. Your answer: c - retina (1 point) Well done. You remembered that the retina has cells that converts light energy into electrical energy. 4. Your answer: true (1 point) Well done! You remembered that both eyes give binocular vision that allows us to judge distance. 5. Your answer: false (1 point) Spot on! You must have remembered two facts. The semi-circular canals are used to sense our head position for balance and the listening parts of two ears are needed to detect the direction of a sound. 6. Your answer: true (1 point) Great stuff! Yes a reflex action is so fast that evasive action is already in progress before impulses have even reached the brain. 7. Your answer: c - cochlea (1 point) Well done! The cochlea converts vibrations into electrical impulses. 8. Your answer: d - auditory nerve (1 point) Well done! yes the auditory nerve carries electrical signals produced by the cochlea to the brain. 9. Your answer: c - cerebellum (1 point) Well done! The cerebellum uses signals from the semi-circular canals to control balance and muscle co-ordination. 10. Your answer: b - medulla (1 point) Well done! Yes the medulla controls the heart and breathing rate.

You scored 9 out of 10 (90%).

Well done! You are revising incredibly well.