The Evolutionary Mystery: Crocodile Survives- ILETS Reading Answer

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Reading Passage

The Evolutionary Mystery: Crocodile Survives

Questions 14-20 

List of Headings

1. The competitors with the dinosaur
2. A historical event for the Supreme survivors

iii. What makes the crocodile the fastest running animal on land

1. Regulated body temperature by the surrounding environment
2. Underwater aid in body structure offered to a successful predator
3. The perfectly designed body for a great land roamer

vii. Slow metabolisms which make crocodile a unique reptile

viii. The favorable features in the impact of a drought

1. Shifting Eating habits and food intake
2. A project on a special mechanism
3. A unique finding has been achieved recently

14 Paragraph A

15 Paragraph B

16 Paragraph C

17 Paragraph D

18 Paragraph E

19 Paragraph F

20 Paragraph G

Questions 21-26

In many places inhabited by crocodilians, most types of the crocodile have evolved a successful scheme to survive in the drought brought by a 21……………………… According to Kennett and Christian’s six-year study of Australian freshwater crocodiles’ aestivation, they found Aestivating crocodiles spent around 22……………………… a year without access to 23……………………… The absolute size of body water pools declined proportionately with 24………………………; thus there is no sign of 25……………………… and other health-damaging impacts in the crocodiles even after an aestivation period. This super capacity helps crocodiles endure the tough drought without slowing their speed of 26……………………… significantly

Reading Answer

14 Answer: ii

Question type: Matching Headings

Answer location: Paragraph A

Answer explanation: Paragraph A the early forms of crocodiles are known as crocodilians. Since they spent most of their life beneath the water, accordingly their body adapted to the aquatic lifestyle. Due to the changes formed within their body shape and tendency to adapt according to the climate they were able to survive when most of the reptiles of their period are just a part of history. In their tenure on Earth, they’ve endured the impacts of meteors, planetary refrigeration, extreme upheavals of the Earth’s tectonic surface, and profound climate change. They were around for the rise and fall of the dinosaurs, and even 65 million years of supposed mammalian dominance have failed to loosen their grip on the environments they inhabit. We understand from these lines that the crocodiles are the supreme survivors of history as they’ve witnessed the impacts of meteors, planetary refrigeration, extreme upheavals, etc. They were also around the rise and extinction of the dinosaurs. Thus, paragraph A illustrates a historical event for the Supreme Survivors. Hence, the answer is A.

15 Answer: vi

Question type: Matching Headings

Answer location: Paragraph B

Answer explanation: Paragraph B explains the body structure of the crocodile. It is stated that the first crocodile-like ancestors appeared about 230 million years ago, with many of the features that make crocs such successful stealth hunters already in place: streamlined body, long tail, protective armor, and long jaws. They have a long head and long tail that helps them to change their direction in the water while moving. They have four legs which are short and webbed. These lines suggest that the crocodiles have the perfectly designed body for great land roaming. Their ability to move on the ground is fascinating. Hence, paragraph B elucidates the perfectly designed and structured body of a great land roamer (crocodile). Thus, the answer is vi.

16 Answer: v

Question type: Matching Headings

Answer location: Paragraph C

Answer explanation: Paragraph C states that crocodilians have no lips. When submerged in their classic ‘sit and wait’ position, their mouths fill with water. The nostrils on the tip of the elongated snout lead into canals that run through bone to open behind the valve – allowing the crocodilian to breathe through its nostrils even though its mouth is underwater. When the animal is totally submerged, another valve seals the nostrils, so the crocodilian can open its mouth to catch prey with no fear of drowning. These lines indicate how crocodiles aid themselves underwater. It is also evident how paragraph C illustrates the underwater aid in body structure offered to a successful predator. Hence, the answer is v.

17 Answer: iv

Question type: Matching Headings

Answer location: Paragraph D

Answer explanation: Paragraph D states that like other reptiles, crocodiles are endothermic animals (cold-blooded, or whose body temperature varies with the temperature of the surrounding environment) and, therefore, need to sunbathe, to raise the temperature of the body. On the contrary, if it is too hot, they prefer being in water or in the shade. Being a cold-blooded species, the crocodilian heart is unique in having an actively controlled valve that can redirect, at will, blood flow away from the lungs and recirculate it around the body, taking oxygen to where it’s needed most. In addition, their metabolism is a very slow one, so, they can survive for long periods without feeding.  Therefore, it is evident from these lines that paragraph D explains the regulated temperature of the crocodiles by the surrounding environment. Hence, the answer is iv.

18 Answer: ix

Question type: Matching Headings

Answer location: Paragraph E

Answer explanation: In paragraph E, it is mentioned that Crocodiles use a very effective technique to catch their prey. The prey remains almost unaware of the fact that there can be any crocodile beneath the water. It is due to the fact that when the crocodile sees its prey it moves underwater without making any noise and significant movement. It keeps only its eyes above the water surface. When it feels it has reached sufficiently close to the target it whistles out of the water with wide-open jaws. 80 percent of their attempts are successful. They have very powerful jaws. Once the prey is trapped in its jaws they swallow it. Their power can be judged by the fact they can kill the wild zebras which come to watery areas in search of water. They do not chew their food. Paragraph E elucidates the eating habits of crocodiles in water as well as land. Their shifting eating habits and food intake are also mentioned in the paragraph. Hence, the answer is ix.

19 Answer: viii

Question type: Matching Headings

Answer location: Paragraph F

Answer explanation: Paragraph F states that in many places inhabited by crocodilians, the hot season brings drought that dries up their hunting grounds and takes away the means to regulate their body temperature. They allowed reptiles to dominate the terrestrial environment. Furthermore, many crocs protect themselves from this by digging burrows and entombing themselves in mud, waiting for months without access to food or water, until the rains arrive. To do this, they sink into a quiescent state called aestivation. We can deduce from these lines that paragraph F illustrates the most favorable characteristics of the impact of drought in the areas where crocodiles live. Thus, the answer is viii.

20 Answer: x

Question type: Matching Headings

Answer location: Paragraph G

Answer explanation: Paragraph G state that the crocodiles spent almost four months a year underground without access to water. Doubly labeled water was used to measure field metabolic rates and water flux, and plasma (and cloacal fluid samples were taken at approximately monthly intervals for some years to monitor the effects of aestivation with respect to the accumulation of nitrogenous wastes and electrolyte concentrations. Double found that the crocodiles’ metabolic engines tick over, producing waste and using up water and fat reserves. Waste products are stored in the urine, which gets increasingly concentrated as the month’s pass. However, the concentration of waste products in the blood changes very little, allowing the crocodiles to function normally. We can deduce from paragraph G that according to the 6-year study of Australian freshwater crocodiles by Kennett and Christian, it is understood that the crocodiles spent around four months a year underground without access to water. Therefore, it is clear that paragraph G explains Kennet and Christian’s project on a special mechanism. Hence, the answer is x.

21 Answer: dry season/ hot season/ dry period

Question type: Summary Completion

Answer location: Paragraph F & G

Answer explanation: The introductory lines of paragraph H states that in many places inhabited by crocodilians, the hot season brings drought that dries up their hunting grounds and takes away the means to regulate their body temperature. In paragraph G, it is mentioned that most (At least nine species of) crocodilians are thought to aestivate during dry periods. Kennett and Christian’s six-year study of Australian freshwater crocodiles – Crocodylus johnstoni (the King Crocodiles). These lines indicate that in many places inhabited by crocodiles, most types of crocodiles have evolved a successful scheme to survive in the drought brought by a hot season or dry period. Thus, the answer is hot season/ dry season/ dry period.

22 Answer: four months

Question type: Summary Completion

Answer location: Paragraph G, line 3

Answer explanation: The 3rd line of paragraph G states that the crocodiles spent almost four months a year underground without access to water. We understand from these lines that according to Kennett and Christian’s study of Australian freshwater crocodiles’ aestivation, they found aestivating crocodiles spent around 4 months a year underground without access to water. Hence, the answer is four months.

23 Answer: water

Question type: Summary Completion

Answer location: Paragraph G, line 3

Answer explanation:

The 3rd line of paragraph G states that the crocodiles spent almost four months a year underground without access to water. These lines indicate that according to Kennett and Christian’s study of Australian freshwater crocodiles’ aestivation, they found aestivating crocodiles spent around 4 months a year underground without access to water. Hence, the answer is water.

24 Answer: body mass

Question type: Summary Completion

Answer location: Paragraph G, line 11

Answer explanation: In the eleventh line of paragraph G, it is stated that though the animals lost water and body mass (just over one-tenth of their initial mass) while underground, the losses were proportional: to emergence. These lines indicate that after the crocodiles had spent four months underground without access to food, as a result of which, the absolute size of body water pools declined proportionately with body mass. Hence, the answer is body mass.

25 Answer: dehydration

Question type: Summary Completion

Answer location: Paragraph G, line 11

Answer explanation: The 11th line of paragraph G states that furthermore, though the animals lost water and body mass (just over one-tenth of their initial mass) while underground, the losses were proportional: on emergence, the aestivating crocodile was not dehydrated and exhibited no detrimental effects such as a decreased growth rate. We understand from paragraph G that when the crocodiles are underground without access to food, their absolute size of body water pools declines proportionately with dehydration. Thus, the answer is dehydration.

26 Answer: growth

Question type: Summary Completion

Answer location: Paragraph G, line 11

Answer explanation: The 11th line of paragraph G states that though the animals lost water and body mass (just over one-tenth of their initial mass) while underground, the losses were proportional: on emergence, the aestivating crocodile was not dehydrated and exhibited no detrimental effects such as a decreased growth rate. These lines indicate that the absolute size of body water pools declined proportionately with body mass, thus, there’s no sign of dehydration and other health-damaging impacts in the crocodiles even after an aestivation period. This super capacity helps crocodiles endure the tough drought without slowing their speed of growth significantly. Thus, the answer is growth.