Which of the following statements about the process of excretion in animals is correct?
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Nephridia are found only in vertebrate animals. |
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Animals with closed circulatory systems usually have capillary beds associated with their excretory organs. |
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In humans and other mammals, urea is produced in the kidneys. |
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Aquatic animals usually secrete their nitrogenous wastes in the form of uric acid. |
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The contractile vacuole of a freshwater protozoan will become more active if the protozoan is placed in seawater. |