Final answer:
Victor Balthazard and Marcelle Lambert's study, 'The Hair of Man and Animals,' focuses on the microscopic studies of hair from both humans and animals, emphasizing its structure, composition, and role in mammals. The correct answer is option: 3) Both humans and animals.
Step-by-step explanation:
In 1910, the French forensic scientists Victor Balthazard and Marcelle Lambert published a comprehensive study titled 'The Hair of Man and Animals' which included numerous microscopic studies of hair from both humans and animals.
The text explores the structure and characteristics of hair, indicating its significance in mammals, and explains its various functions, including protection from UV light and as a sensory tool. Hair, being primarily composed of the protein keratin, is a key feature in mammals, including humans, serving both physiological and social roles.
The study of Balthazard and Lambert has been foundational in the understanding of forensic science, particularly in the examination of hair as evidence in criminal investigations.