What is a role of the kidney in freshwater fish?
(A) To remove water from the fish
(B) To absorb salt from the environment
(C) To excrete concentrated urine from the fish
(D) To decrease nitrogenous waste lost to the environment - HSC - SSCE Biology - Question 14 - 2012 - Paper 1
Question 14
What is a role of the kidney in freshwater fish?
(A) To remove water from the fish
(B) To absorb salt from the environment
(C) To excrete concentrated urine from th... show full transcript
Worked Solution & Example Answer:What is a role of the kidney in freshwater fish?
(A) To remove water from the fish
(B) To absorb salt from the environment
(C) To excrete concentrated urine from the fish
(D) To decrease nitrogenous waste lost to the environment - HSC - SSCE Biology - Question 14 - 2012 - Paper 1
Step 1
To remove water from the fish
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Answer
Freshwater fish are constantly gaining water through osmosis due to the lower solute concentration of their environment compared to their body fluids. The kidneys play a crucial role in regulating this influx of water by excreting dilute urine, which helps to remove excess water from the body.
Step 2
To absorb salt from the environment
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Answer
While freshwater fish do require some salt for physiological functions, they typically do not absorb salt directly from the environment. Instead, they actively uptake necessary ions through their gills.
Step 3
To excrete concentrated urine from the fish
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Answer
On the contrary, freshwater fish excrete dilute urine rather than concentrated urine. This adaptation helps them eliminate excess water while retaining essential ions.
Step 4
To decrease nitrogenous waste lost to the environment
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Answer
Freshwater fish excrete nitrogenous wastes primarily in the form of ammonia, which is highly soluble in water. Their kidneys are designed to help minimize the loss of nitrogenous waste to the surrounding environment.
