424 BIOLOGY FOR BEGINNERS 



(>) How we hear, 

 (c) Care of ears. 



6. Sight. 



(a) Structure of eyes. 

 Coats, 



Sclerotic, white, thick, protective, cornea in front. 

 Choroid, blood vessels and pigment, iris in front. 

 Retina, dark, complicated, receives impressions. 

 Lens, convex, adjustable by muscles. 

 (&) How we see. 



(c) Protection of the eye. 



(d) The living camera. 



(e) Defects of the eye. 



