In mammals, air enters lungs through tubes called , which branch into smaller tubules called , which extend out to tiny air sacs called . trachea; bronchioles; spongy tissue. bronchi; bronchioles; alveoli. bronchi; alveoli; gills.

The answer is Bronchi; Bronchioles; Alveoli.

Explanation:

Air enters the lungs through the Bronchi which are two terminal branches of the trachea that enters each lung. Within the lung, the bronchi branch extensively, giving rise to increasingly thinner ducts, known as the bronchioles, which terminate in the alveolar ducts. The alveolar ducts lead to small sac-shaped structures surrounded by a dense network of blood capillaries called pulmonary alveoli.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.