Idaho POST Practice Exam 2025 – All-in-One Resource to Master the Peace Officer Standards and Training!

Latent prints, which are fingerprints that are not immediately visible, are primarily composed of moisture and various substances secreted from the skin. The correct answer indicates that latent prints are primarily made up of water, as human skin can excrete a substantial amount of moisture through sweat glands. This moisture also contains oils, salts, and other organic materials, but the predominant component by volume is indeed water.

Choosing the view that latent prints consist mainly of another substance, like oil or dirt, does not accurately reflect the biological composition of these prints. While oil does play a role as it can also be found in the sebaceous materials emitted from glands, it does not constitute the majority like water does. Similarly, dirt and alcohol would not be significant components of latent prints. This understanding is crucial for law enforcement professionals in processing and analyzing latent prints effectively when investigating crime scenes.