Radiology Practice Test

A radiolucent structure appears as black on an x-ray because it is able to easily transmit x-rays, making it less dense than the surrounding structures. White (A) would indicate a radiopaque structure, meaning it is more dense and blocks the x-rays. Gray (C) may be seen as a range of shades depending on the degree of density, but it would not be consistently black. Yellow (D) is not a common color represented on x-rays and would not accurately represent the level of density of a radiolucent structure. Overall, the contrast between black and white on an x-ray allows for clearer visualization and distinction of different structures within the body.