This item is a pseudo-discrete, since we do not need the passage to answer it. We have to determine what kind of animal, from the given choices, excretes its wastes using the smallest amount of water. To do this, we have to first understand why excreting only limited amounts of water could be advantageous for an animal. The advantages of not requiring large amounts of water for nitrogen excretion include reduced water intake needs and decreased volumes of excretion. We need to establish which animal would benefit from such reduced water excretion. Since this is a generalized prediction, we should turn to the answer choices and apply our critical assessment skills. Would a wild pig benefit from reduced water excretion? No, this is not the case with such an
animal, so we eliminate choice (A). What about a flying bird? Due to its limited access to water and the difficulties of storing large volumes of urine while in flight, such an animal could be expected to benefit from such reduced water excretion. Choice (B) looks promising, but lets quickly address the remaining options. Both choices (C) and (D) are examples of fish; since we cant distinguish between them (and they cant both be correct answers), we can also eliminate choices (C) and (D). To further verify choice (B) as the correct answer,
we might remember that bird excretions are almost solid, indicating that they do not excrete much water.
(what?! yeah, let me just go to the chapter on "bird poo" ) The correct answer is indeed
choice (B).
(A) Distortion. A wild pig should have access to water and does not benefit from the decreased volumes of excretion.
(C) Distortion. A shark should have access to water and does not benefit from the decreased volumes of excretion.
(D) Distortion. A fish should have access to water and does not benefit from the decreased volumes of excretion.
