Most spiders have four pairs of eyes on the top-front area of the cephalothorax, arranged in patterns that vary from one family to another.[8] The pair at the front are of the type called pigment-cup ocelli ("little eyes"), which in most arthropods are only capable of detecting the direction from which light is coming, using the shadow cast by the walls of the cup. However the main eyes at the front of spiders' heads are pigment-cup ocelli that are capable of forming images.[16][17] The other eyes are thought to be derived from the compound eyes of the ancestral chelicerates, but no longer have the separate facets typical of compound eyes
سلام ..ممنون از سایت خوبتون....من پشت کنکوری هستم.هر روز که برنامه ریزی میکنم واسه ی روز بعد اصلا نمیتونم اجراش کنم,پارسال هم ک قبول نشدم اینطور بودم نمیتونستم برنامه ریزی هامو اجرا کنم..خیلی ناراحتم که اینجوریم,,,لطفا کمکم کنید
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