Underproduction of pulmonary surfactant in irds leads to decreased compliance of alveolar tissue. based upon this information, which of the following must be true regarding pulmonary surfactant? a. its adsorption to the water-alveolar interface increases surface tension, preventing alveolar collapse due to intra-thoracic pressure. b. its absence decreases the minimum radial size of alveoli able to avoid collapse at a given pressure of inspired air. c. its adsorption to the water-alveolar interface decreases surface tension, decreasing the pressure difference required to inflate the airway. d. its presence increases the efficiency of gas exchange across the alveolar membrane by decreasing the surface area of the alveolus at a given pressure of inspired air.

Option (C).

Explanation:

The alveoli is the main site of the exchange of gases in the human beings. The gases gets exchanged between the atmosphere, lungs and the body tissue.

The contraction of external intercostal muscles and diaphragm during inspiration leads to thoracic cavity expansion. This result in decrease in intrapleural pressure as compared with the atmospheric pressure. The air enters in the lungs. The elastic recoiling of the surface tension of airway and the water oppose the alceoli expansion. The surfactant gets adsorb at the water surface. This reduces surface tension, the force that resist expansion. The pulmonary compilance get increase.

Thus, the correct answer is option (C).

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.