The use of __________ was initially designed as a set of rules that people could follow if they found themselves in unfamiliar surroundings

Which of the following describes radiolucent distortion surrounding the dense radiopaque appearance of the metal object on an image?

A) Slicing B) Cupping C) Fanning D) Streaking

The __________ __________ is a small, yellowish area containing the fovea centralis, in which visual perception is most acute?

Fill in the blank(s) with correct word