Which prints are not visible to the naked eye but are crucial in forensic investigations?

Latent prints are the correct answer because they are composed of the natural oils and sweat from the skin, which make them not visible to the naked eye. These prints can be found on various surfaces where an individual has touched, and their visibility is often enhanced through techniques such as powder dusting or chemical treatments.

In forensic investigations, latent prints are of crucial importance as they can link a suspect to a crime scene or item. They require specialized techniques to be rendered visible and are often collected using methods that preserve the print without damaging the underlying evidence.

In comparison, patent prints are visible, made through the transfer of blood, ink, or other substances onto a surface. Plastic prints are three-dimensional impressions left in soft materials like wax or clay, and dust prints refer to marks left in dust that can be easily seen. While these types of prints are significant in forensic science, latent prints hold substantial value in investigations due to their ability to provide unique identifiers without being immediately seen.