Vertebrates have developed various renal structures for osmoregulation based on their habitats. Bony fish that live in seawater drink large amounts of seawater and use cells in gills to pump excess salt out of the body. This is in response to:
A. a loss of water by active transport to their hypertonic surroundings.
B. a loss of salt to their surroundings.
C. an influx of water by osmosis into their tissues.
D. a need to maintain their tissues in a hypertonic state.
Answer is D.
Explanation: "Different organisms have different needs to maintain their water balance, depending on the environment they live in. Bony fish living in saltwater maintain hypoosmotic body fluids. The hyperosmotic water they live in tends to draw water out of their body by osmosis. They can obtain water by ingesting ocean water, but this raises their internal osmolarity. They excrete salt, then, to lower their internal osmolarity."
First, I look at the question: they consume large amounts of seawater and spit out salt. This means that they maintain hypoosmotic conditions. Water moves out by osmosis, and they drink + desalinate to maintain osmolarity.
So they try to keep their tissue in a HYPOosmotic state, right? Not a hyperosmotic. I don't understand why D is correct. Actually I don't find any of the answers satisfactory...
A. a loss of water by active transport to their hypertonic surroundings.
B. a loss of salt to their surroundings.
C. an influx of water by osmosis into their tissues.
D. a need to maintain their tissues in a hypertonic state.
Answer is D.
Explanation: "Different organisms have different needs to maintain their water balance, depending on the environment they live in. Bony fish living in saltwater maintain hypoosmotic body fluids. The hyperosmotic water they live in tends to draw water out of their body by osmosis. They can obtain water by ingesting ocean water, but this raises their internal osmolarity. They excrete salt, then, to lower their internal osmolarity."
First, I look at the question: they consume large amounts of seawater and spit out salt. This means that they maintain hypoosmotic conditions. Water moves out by osmosis, and they drink + desalinate to maintain osmolarity.
So they try to keep their tissue in a HYPOosmotic state, right? Not a hyperosmotic. I don't understand why D is correct. Actually I don't find any of the answers satisfactory...