[Campbell Biology P.993] Based on Mary Ellen Avery's experiment and findings presented in Fi... | Practice Question

Based on Mary Ellen Avery's experiment and findings presented in Figure 42.25, what is the primary cause of Respiratory Distress Syndrome RDS in preterm infants?

  • A: A viral infection causing lung inflammation and fluid buildup.
  • B: The lack of a surface-tension-reducing substance (surfactant) in the alveoli, leading to higher surface tension.
  • C: Premature lung development causing an inability to inhale sufficient air.
  • D: An excess amount of surfactant leading to lung collapse.

Explanation

Mary Ellen Avery's experiment concluded that RDS in infants is caused by the lack of a substance later identified as surfactant that reduces surface tension in the alveoli. The graph supports this by showing higher surface tension in infants who died of RDS, especially those with larger body mass who should have developed surfactant.