What are the membranes covering the lungs called?

Cornea transplant in humans is almost never rejected. This is because

Which of the following organs is not located in the thoracic cavity?

What is the function of the epiglottis?

Select the correct statements about alveoli from the following.
$i$. Air sac of each terminal bronchiole shows $10$ to $12$ alveoli.
$ii$. Each alveolus is surrounded by a network of capillaries.
$iii$. They are lined by ciliated pseudostratified epithelium.
$iv$. They provide surface area for exchange of gases.
$v$. There are about $700$ million alveoli in the lungs.

The laryngopharynx opens into