[Campbell Biology P.1046] Based on the table in Concept 44.1, which of the following statemen... | Practice Question

Based on the table in Concept 44.1, which of the following statements correctly describes the osmoregulation strategy of a freshwater fish compared to a marine bony fish?

  • A: Freshwater fish drink large amounts of water, while marine bony fish do not.
  • B: Freshwater fish produce a large volume of dilute urine, whereas marine bony fish produce a small volume of slightly concentrated urine.
  • C: Both freshwater and marine bony fish actively transport salt into their bodies through gills.
  • D: Freshwater fish tend to lose water to their environment, while marine bony fish tend to gain water.

Explanation

Freshwater fish live in a hypotonic environment, meaning their body fluids are saltier than the surrounding water. They constantly gain water by osmosis and lose salt by diffusion. To compensate, they do not drink water and excrete a large volume of very dilute urine to eliminate excess water while retaining salts. Marine bony fish, in contrast, live in a hypertonic environment, causing them to constantly lose water by osmosis and gain salt by diffusion. They drink large amounts of seawater, excrete excess salts through gills, and produce a small volume of slightly concentrated urine to conserve water.