What type of evidence does biological evidence include?

Biological evidence encompasses any material derived from living organisms that can provide insights in a forensic context. This includes human and animal remains, bodily fluids such as blood or saliva, and tissues. Such evidence is critical in numerous forensic investigations because it can be used for DNA analysis, which helps in identifying individuals or linking them to a crime. The presence of biological evidence can establish connections between a suspect and a victim or crime scene, making it vital for criminal investigations.

The other options do not fit within the category of biological evidence. Electronic communications primarily pertain to digital interactions and do not involve organic materials. Photographs taken at a crime scene serve as visual documentation but lack the biological component necessary for forensic analysis in this context. Records of financial transactions are financial documents that provide monetary information and are unrelated to biological evidence. Thus, the correct choice highlights the essence of biological evidence in forensic science.