Alveolar pores
a. allow gases to transfer from the alveoli to the blood.
b. allow pleural fluid to enter the alveoli and keep their walls from sticking together.
c. are the openings between the alveolar duct and the alveolus.
d. equalize air pressure throughout the lung.

The answer is option d. equalize air pressure throughout the lung.

Explanation:

Alveolar pores equalize air pressure throughout the lung. Thin alveolar septa separate adjacent alveoli. Adjacent alveoli have connections via small openings, called pores of Kohn, that allow for collateral airflow and equalization of pressure between alveoli. The control of opening or closing of alveoli to regulate ventilation occurs at common alveolar openings by smooth muscle projections called alveolar cusps.

The alveolar septum has numerous capillaries and thin walls for gas exchange. In addition to capillary endothelial cells, the alveolar septum contains Type I pneumocytes that are very thin and line the alveoli, as well as Type II pneumocytes that secrete (DPPT) surfactant to decrease alveolar surface tension. Alveolar macrophages, also known as dust cells, are active in defending against pathogens and irritants.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.