**Core Concept**
Alveoli are the functional units of the lungs where gas exchange occurs. Maintaining their surface tension is crucial to prevent alveolar collapse and ensure efficient gas exchange. Surfactants play a vital role in reducing the surface tension within the alveoli.

**Why the Correct Answer is Right**
Surfactants are a complex mixture of phospholipids and proteins that line the alveolar surface. They reduce the surface tension within the alveoli, making it easier for the lungs to expand during inspiration. This is particularly important during expiration, as it prevents the alveoli from collapsing. Surfactants work by creating a film that covers the surface of the alveoli, reducing the energy required for expansion. This mechanism is critical in neonates, as they have a higher alveolar surface tension due to the immaturity of their surfactant system.

**Why Each Wrong Option is Incorrect**
**Option B:** Glycoproteins are involved in various biological processes, including cell signaling and immune responses. However, they do not play a direct role in reducing alveolar surface tension.
**Option C:** Bohr's effect refers to the decrease in oxygen affinity of hemoglobin when the pH of the blood increases. While it's an important concept in respiratory physiology, it's not directly related to maintaining alveolar dryness.
**Option D:** The term "Effect" is too vague and doesn't provide any specific information about the mechanism of maintaining alveolar dryness.

**Clinical Pearl / High-Yield Fact**
Surfactant deficiency is a common cause of respiratory distress syndrome in preterm infants. Administering surfactant replacement therapy can significantly improve their lung function and survival rates.

**✓ Correct Answer: A. Surfactants**