[Campbell Biology P.971] A gastrovascular cavity typically serves both digestion and substan... | Practice Question

A gastrovascular cavity typically serves both digestion and substance distribution. Based on the text and the 'WHAT IF?' prompt, if a gastrovascular cavity were open at two ends, allowing fluid to enter one end and leave the other, what would be the most significant impact on its functions?

  • A: Digestion would become more efficient as food particles could be continuously flushed through the system, preventing accumulation.
  • B: Gas exchange would be enhanced due to constant unidirectional flow, but digestion would be compromised as digestive enzymes and nutrients would be flushed out.
  • C: Both gas exchange and digestion would significantly improve because fresh water would continuously flow through the cavity.
  • D: The primary function of substance distribution would be lost, as the cavity would no longer act as a closed system for internal circulation.

Explanation

The 'WHAT IF?' prompt asks how having the cavity open at two ends, with fluid entering one and leaving the other, would affect its functions in gas exchange and digestion. A constant unidirectional flow would likely enhance gas exchange by continuously bringing in fresh oxygenated water. However, for digestion, the cavity relies on retaining food and digestive enzymes for sufficient time. A continuous flow-through system would flush out digestive enzymes and partially digested food before full nutrient absorption, thus severely compromising digestion.