Question

most sharks must swim constantly to keep oxygenated water flowing over their gills. however, some shark species have an extra organ that allows them to breathe while staying still, which requires less energy. for what type of environment would this adaptation be most advantageous to survival?
a. one with little oxygen in the water
b. one where the water is more shallow
c. one where food sources are scarce
d. one where humans frequently fish

Explanation:

The adaptation allows sharks to conserve energy (by not constantly swimming). In an environment with scarce food sources, conserving energy (using less energy as they don't need to swim constantly to breathe) is crucial for survival as they may have to wait longer between meals. Option A: If there's little oxygen, sharks (even with the organ) might still struggle as the main issue is oxygen availability, not energy - related to breathing while still. Option B: Water shallowness doesn't directly relate to the energy - saving aspect of the adaptation. Option D: Human fishing pressure is more about predation/harvesting risk, not directly tied to the energy - saving breathing adaptation.

Answer:

C. one where food sources are scarce