occur(s) when blood collects in a level (not sloped) and undisturbed place, while occur(s) when an object blocks the deposition of blood spatter onto a target surface or object and the spatter is deposited onto the object or person instead. A pool of blood, voids/emtpy spaces Voids/emtpy spaces, a pool of blood Skeletonization, a pool of blood A pool of blood, skeletonization

Explanation:

Analysis of blood stain patterns are significant step in crime investigations. They often give the idea of the type of weapon used , the manner of crime and the time of crime.

When blood drops on a flat surface, it does not flow but  dries there. The drying time of blood is possible to be calculated. The drying time of the blood can give an idea about when the events associated with crime occurred.

Since voids are created when any object blocks the blood from spattering on the target object, an impression of the blocking object is formed. it is often the body of the victim or the weapon of crime. So an idea about victims position and shape of weapon can be assumed by void analysis.

the fossil record provides evidence of a common ancestor to many species.