Which of the following describes the characteristic of epiglottis?

The characteristic of epiglottitis includes both swollen aryepiglottic folds and narrowing of the vocal cords, which is why the correct answer encompasses both of those aspects.

In cases of epiglottitis, inflammation of the epiglottis and surrounding structures is typical. This inflammation can lead to the swelling of the aryepiglottic folds, which are the tissue folds that extend from the epiglottis to the arytenoid cartilages in the larynx. The swelling in this area can obstruct airflow, making it difficult for patients to breathe, and is a critical sign of this condition.

Additionally, when the vocal cords become narrowed due to inflammatory processes, it further complicates breathing and can impact the patient's voice, leading to stridor or a hoarse sound, especially in a pediatric population.

The other options, such as a flattened, swollen trachea, may describe other respiratory conditions but do not specifically relate to the characteristic features typically associated with epiglottitis. Therefore, both swollen aryepiglottic folds and narrowing of the vocal cords are key indicators in the assessment of this condition.