A **full-face helmet** is a type of helmet designed to offer complete protection to both the **face** and the **head**. This type of helmet covers not only the upper part of the skull but also the lower part of the face and the jaw, making it safer in the event of an accident.

- In the event of a blow, the full-face helmet distributes the force of the impact across its entire surface, preventing it from concentrating in a single point and thus reducing the risk of serious injuries.
- Additionally, it protects the face and head from burns when sliding on the ground after a fall.
- It also prevents sharp objects, such as stones or metal, from penetrating the head.

For these reasons, a full-face helmet is essential for protecting both the face and the head, which makes the correct answer that it protects both parts.