ACT reading practice test 42

DIRECTIONS: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.


Natural Science

This passage is adapted from "Feces, Bite Marks Flesh Out Giant Dino-Eating Crocs" by Brian Handwekr (© 2010 National Geographic).

Rock-hard feces and oddly bitten bones are helping to flesh out one of the biggest crocs of prehistory. As long as a stretch limo, Deinosuchus-"terrible crocodile"- likely prowled shallow waters and hunted dinosaurs its

5 own size, the evidence suggests. Paleontologists announced their conclusions after analyzing pieces of 79-million-year-old fossilized dung, or coprolites, that appear to be the first known droppings from Deinosuchus. The discoveries offer the newest insights

10 into the lives of the giant crocs, which roamed much of what is now the United States and northern Mexico.

Sand and shell fragments in the droppings, found within the last few years near a Georgia stream, suggest the croc preferred estuaries, where, at least in Georgia-

15 home to a great concentration of Deinosuchus remains- it probably dined mostly on sea turtles. Despite the Georgia Deinosuchus's relatively docile prey, "we're pretty sure it was the apex predator in this region," said Samantha Harrell of Columbus State University in

20 Georgia, who presented her research March 17 at a Geological Society of America meeting in Baltimore.

The team also found a fossilized shark tooth embedded in the outside of a coprolite. But because the tooth bears no signs of having been digested, the team suspects

25 a shark left the tooth behind when scavenging on Deinosuchus droppings. What the researchers didn't find in the feces are bone or other bits of undigested animals. "That's actually good," Harrell said, "because both modern and ancient crocs have digestive juices that eat up

30 bone, horns, teeth, and just about everything else"-so the "empty" dung supports the idea that the feces are from a croc.

Outside Georgia, Deinosuchus apparently took on slightly more challenging prey, according to older bitemark

35 evidence, which Columbus State paleontologist David R. Schwimmer presented alongside Harrell at the meeting. Deinosuchus tooth impressions in the bones of their prey tell the tale of titanic battles in which the 29-foot crocs took down dinosaurs their own size-

40 including the T. rex relatives Appalachiosaurus montgomeriensis and Albertosaurus.

"One of the marks shows signs that the bone was healed, which means that the animal survived the bite," Schwimmer said. "That proves that at least this one

45 specimen was obviously a predator and not scavenging." Schwimmer first noticed strange, dimpled, egg-shaped indentations in Georgia sea turtle fossils. Later he saw similar marks in dinosaur bones in Big Bend National Park in Texas and in the New Jersey State Museum.

50 "I realized these bites were from something with really powerful jaws and lots of teeth," he said. "And it was pretty obvious that this big, blunt-toothed croc was the source. There was nothing else I've found that could create blunt bite marks like these."

55 Tooth marks, though, can show us only part of the picture, said Stephanie Drumheller, an expert on ancient crocodile bites. "Modern crocodilians"-crocodiles, alligators, and related extinct forms-"are more than capable of swallowing smaller prey whole and disarticulating

60 larger animals into bite-sized pieces," leaving little evidence behind, said Drumheller, a Ph.D. candidate in geoscience at the University of Iowa. "We can infer that a giant like Deinosuchus would be capable of even more destructive feeding behaviors."

65 The bite-mark evidence that does exist, though, raises a question: Why would a croc capable of taking down big, meaty dinosaurs waste its energy on turtles In a word: location. Modern crocs, which hunt a wide range of prey, eat whatever's available in their areas. The same

70 factor may have determined whether Deinosuchus individuals feasted largely on turtles or dinosaurs or other prey, Drumheller said.

North America-born Deinosuchus also underscores that giant crocs arose at different places and times, said

75 University of Chicago paleontologist Paul Sereno, who discovered 110-million-year-old Sarcosuchus imperator- aka SuperCroc-in Niger. "In Deinosuchus, and independently in SuperCroc, we have two lineages, one older than the other, that prove crocodile bodies grew to a

80 gargantuan size-to dinosaur size," said Sereno, a National Geographic Society explorer-in-residence.

Deinosuchus, which lived just before the close of the Cretaceous period, is more closely related to modern croc lineages than SuperCroc-yet still faded to extinction.

80 What happened to these prehistoric leviathans A fully grown giant male croc likely would have had to commandeer miles of river territory to regularly find enough prey to sustain itself, Sereno explained. So space constraints likely kept population numbers low-making

90 the giant crocs vulnerable to extinction in tough times. "It appears that every once in a while the right conditions arise for giant crocs," Sereno said. "But they usually don't last."

1. The main idea of the passage is that:

A. giant crocodiles probably still exist.
B. ancient giant crocodiles hunted dinosaurs.
C. dinosaurs were actually a type of crocodile.
D. all crocodiles will eventually go extinct.

2. Which of the following phrases most accurately describes how crocodilian feeding habits are described in the passage?

F. Destructive but mindless
G. Uniform and predatory
H. Voracious but cowardly
J. Varied and opportunistic

3. The passage most strongly supports which of the following inferences about crocodilian size?

A. Crocodilians tend to grow as large as conditions permit them to.
B. Freshwater crocodilians are able to grow larger than saltwater ones.
C. Crocodilians always grow large enough to ensure that they are the local apex predator.
D. It will never again be possible for crododilians to grow as large as Deinosuchus.

4. Which of the following is NOT mentioned in the passage as a habitat of Deinosuchus?

F. Georgia
G. Mexico
H. Niger
J. Texas

5. The main purpose of the third paragraph (lines 22-32) is to:

A. argue that ancient crocodiles preyed on sharks.
B. argue that sharks preyed on ancient crocodiles.
C. establish that the dung in question is crocodilian in origin.
D. suggest that Deinosuchus may not always have been carnivorous.

6. According to the passage, one major similarity between Deinosuchus and modern crocodilians is their:

F. teeth.
G. diet.
H. range.
J. digestive processes.

7. As it is used in line 78, the word lineages most nearly means:

A. habits.
B. bloodlines.
C. behaviors.
D. imitators.

8. According to the passage, the best evidence that Deinosuchus preyed on dinosaurs was obtained from:

F. bones.
G. dung.
H. teeth.
J. eggs.

9. Based on the passage, it can reasonably be inferred that a crocodilian species whose main food source dries up will:

A. immediately starve to extinction.
B. begin eating something else.
C. decrease in size.
D. decrease its range.

10. Based on the passage, the existence of giant crocodilians can best be described as:

F. ideal.
G. unavoidable.
H. destructive.
J. anomalous.