What distinguishing feature do head and body lice possess?

Head and body lice are characterized by their ability to lay sticky eggs, commonly known as nits, that adhere firmly to the host's hair or clothing fibers. This feature is crucial for their lifecycle, as the nits must remain close to the warmth and nourishment provided by the host in order to hatch and produce new lice. The sticky nature of the eggs ensures they do not easily come off and are protected from external environmental factors. This adaptation aids in the propagation of the lice population, making it a significant aspect of their biology.

The other options, which include having wings or the ability to fly, are incorrect because both head and body lice are wingless insects. They are also not capable of flight, relying instead on crawling to spread from one host to another. Additionally, the statement about not attaching eggs to the host contradicts the biological habits of these lice, as their reproductive strategy involves firmly sticking the eggs to ensure their survival and successful development.