Which evidence may be found on a victim in a sexual assault case?

The presence of saliva, semen, and skin tissue on a victim in a sexual assault case is significant because these biological materials can provide critical evidence for forensic analysis. Each of these substances can contain DNA, which is essential for identifying either the perpetrator or confirming a victim's identity.

Saliva can be transferred during a sexual assault, especially if there was any oral contact. Semen is a common form of evidence in cases of penetration or sexual intercourse, and it can provide conclusive DNA evidence linking a suspect to the crime. Skin tissue, which may be transferred during physical struggle or contact, can also contain DNA that could be matched to a potential assailant, adding another layer of evidence for prosecution.

The other choices either limit the scope of possible evidence to very specific materials or suggest that no relevant evidence would be available, which is not accurate in the context of a sexual assault investigation. Recognizing the full range of biological evidence that may be found on a victim is crucial for law enforcement and forensic professionals in building a comprehensive case.