Which type of stain may also include gushes and splashes?

The correct answer relates to impact stains, which typically occur when a force is applied to a blood source, causing it to break apart and disperse. These stains can indeed result in various patterns, including gushes and splashes, depending on the intensity and angle of the impact.

Impact stains are characterized by the physical interaction of blood with another surface, which can create a wide range of patterns, from small droplets to larger splashes, depending on the circumstances surrounding the event. This phenomenon often occurs in violent incidents where blood is expelled due to a sudden impact, such as a beating or a stabbing, leading to these distinct patterns that forensic experts analyze for insights into the event's dynamics.

Other stain types listed do not emphasize the same fluid dynamics associated with force application. Drops, flows, and pools involve blood settling in a liquid state without the violent force associated with impact. Expired splatter generally refers to blood expelled from a wound or mouth in a less forceful manner, while gunshot injuries focus specifically on the gunshot impact rather than the broader category of stains resulting from physical interaction.