Consider: To measure its distance from an object, the jumping spider exploits a unique feature of its two principal eyes, each of which has a “staircase ” retina with multiple layers.
تأمل في ما يلي :‏ كي يقيس العنكبوت القافز بُعده عن غرض معين ،‏ يستغل ميزة تنفرد بها عيناه الرئيسيتان .‏