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Reading Comprehension – Caecilians

“Toothy worm-like creatures called caecilians have smooth, shiny skin and already look a lot like snakes. Still, scientists were surprised to discover some of these legless animals may have venomous saliva—possibly the first example ever found in amphibians.

Nearly 200 caecilian species wiggle through tropical forests the world over, ranging from the 3.5-inch-long Idiocranium russell in Cameroon to the nearly five-foot-long giant known as Caecilia thompsoni in Colombia. Most of the animals dwell underground, which is why “caecilians are maybe the most unknown group of vertebrates,” says Carlos Jared, an evolutionary biologist at the Butantan Institute in São Paulo, Brazil, and author of a new study on the animals. Some species are so adapted to subterranean life, they’ve completely lost their eyes.

Scientists already knew caecilians have three rows of needle-nosed teeth—two on the top and one on the bottom—that likely help the predators catch and gulp down earthworms. But while looking at caecilians captured in Brazil, Jared discovered a never-before-described set of dental glands that produce saliva and, possibly, venomous enzymes. But, he cautions, further analysis is needed to confirm caecilian saliva is truly venomous. If it is, the implications are striking, says Emma Sherratt, an evolutionary biologist at University of Adelaide in Australia who was not part of the study. For one, it would mean that venom evolved independently in both amphibians and reptiles, which would reconfigure what we know about how venom evolved.” Source:

Which one of the following claims does the passage provide most support for?

A. According to new research, most caecilians have a set of dental glands that produce saliva and venomous enzymes.
B. Emma Sheratt is the biologist in charge of evolutionary development at the University of Adelaide in Australia.
C. Some caecilian species can grow to be at least three feet long.
D. Venom did evolve independently in amphibians and reptiles.
E. Caecilians are toothy worm-like invertebrates that dwell underground.


CORRECT ANSWER = (C) – According to the passage “Caecilia Thompsoni” grows to be nearly five-foot long.

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