Examlex
The Inka had no writing system, but kept records using a system of knotted strings called quipu.
Controlled
Pertains to experimental conditions that are manipulated or regulated by the researcher to isolate cause and effect relationships.
Human Eye
A complex organ capable of receiving visual images, which are then processed by the brain, it comprises structures such as the cornea, iris, lens, and retina.
Camera
A device for capturing visual images in the form of photographs, video recordings, or digitally.
Retina
The retina is the light-sensitive layer of tissue at the back of the eye, which detects light and converts it into neural signals for processing by the brain.