Which of the following tissues have approximately the same density?

The correct choice is based on the understanding that muscle and water have similar densities, which is crucial in radiographic imaging. In radiography, the density of tissues is important because it affects the absorption of X-rays, influencing how images are formed.

Muscle has a density that is relatively close to that of water, typically around 1.05 g/cm³ for muscle and approximately 1 g/cm³ for water. This similarity means that in imaging, muscle and water can produce comparable levels of radiographic contrast, making it easier for technicians to identify and analyze images.

Other combinations in the question vary in density. For instance, fat has a lower density than both muscle and water, around 0.9 g/cm³, leading to different interactions with X-ray radiation. Therefore, while muscle and water exhibit similar densities, fat diverges significantly from this comparison, demonstrating how tissue density plays a pivotal role in radiographic practices.