What does a mixture of surfactants contain?

Correct option is A

Ans (a)
Sol. Protein and lipid: Pulmonary surfactants are a mixture of lipids (around 90%) and surfactant proteins (around 10%). These components work together to reduce the surface tension in the alveoli, preventing their collapse during exhalation. This is the correct answer.
Mucus and chloride: These are unrelated to the composition of surfactants. Mucus is secreted for protection and trapping particles, while chloride ions are involved in maintaining electrolyte balance.
Protein and chloride: Chloride is not a component of surfactants. Proteins play a role in surfactants but are not paired with chloride.
Lipid and chloride: Chloride does not contribute to surfactant function, and this combination is incorrect.