Surfactant to prevent the alveoli from collapsing by

The correct answer will be- by lowering the surface tension at air/liquid transition.

Explanation:

Pulmonary surfactant is the mixture of proteins and lipids produced by the type II epithelial cells.  

The surfactant is selected into the alveolar sacs where the surfactant reduces the surface tension of the air/liquid interface to 1 mN/m. The lipid content of the surfactant called or DPPC forms a surface film which lowers the surface tension.

This power surface tension reduces the work of breathing and thus prevent the alveolar sac from rupture or collapse.

Thus, by lowering the surface tension at air/liquid transition is the correct answer.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?