[Campbell Biology P.993] Considering the "WHAT IF?" question and the overall conclusion of A... | Practice Question

Considering the "WHAT IF?" question and the overall conclusion of Avery's study, what relationship would you expect between the amount of surfactant in infant lung samples and infant body mass, especially concerning preterm infants?

  • A: The amount of surfactant would be inversely proportional to body mass, meaning larger infants would have less surfactant.
  • B: Surfactant levels would be consistently high across all body masses, as it's essential for lung function regardless of size.
  • C: There would be a direct correlation: infants with larger body mass (especially above 1,200 g or born after 33 weeks) would tend to have higher amounts of surfactant.
  • D: The amount of surfactant would only be measurable in infants who died of RDS, as it's a disease-specific marker.

Explanation

The text states that surfactant is "not normally produced until a fetus reaches this size" referring to ≥1,200 g and after 33 weeks of gestation . This implies that as body mass increases especially reaching a certain developmental stage , the amount of surfactant produced also increases, leading to lower surface tension and better lung function.