The guards the opening at the back of the throat that leads into the trachea.
pharynx
epiglottis
larynx
glottis

The correct answer would be the third option. The larynx guards the opening at the back of the throat that leads into the trachea. It is a flexible and tough section in the respiratory tract that connects the pharynx and the trachea. It is an important part of the respiratory system as it allows air to pass through and keeping drink and food from blocking the airway. It is also the so called "voice box" since it has the vocal folds that help us produce sounds. The sounds are produced by the motion of the air in the larynx and the vocal folds which are movable folds found in the mucous membrane.

11. gene12. allele13. crossing over14. linked15. gene16. x17. males, femalesapologies if numbers are out of order.