Sea turtle hatchlings leaving their hatching grounds on Florida beaches reach ocean currents by swimming to the northeast, as defined by the north of the Earth\’s magnetic field. Florida hatchlings placed in a large indoor tank also swim toward the northeast. But when the tank is surrounded by an artificial magnetic field twice as strong as the Earth\’s field and opposite in direction, the hatchlings swim in the direction opposite to that in which they swim without the artificial magnetic field.
The information in the statements above most strongly supports which one of the following?
(A) Once baby sea turtles reach the open sea, they join groups of adults in the North Atlantic.
(B) The dirction in which ocean currents flow is determined by the magnetic field of the Earth.
(C) Baby sea turtles are able to sense the magnetic field of the Earth.
(D) No sea turtle ever returns to the beach where it hatched.
(E) If a sea turtle hatches on the coast of Africa, it will swim toward the southwest.
This question asks you to draw an inference based on the information presented. It is not enough that a response be true, if the information in that response is irrelevant to the information presented. Nor is it sufficient that a response present information that is merely consistent with the information presented in the passage; the best answer must present information that is supported by the information in the passage.
A. Incorrect. Since the passage does not say anything about adult sea turtles, or about the location of the adults, this claim is not supported by information in the passage.
B. Incorrect. The passage does not provide any information about the relation between ocean currents and the magnetic field of the Earth, and so this response is not correct.
C. Correct. Though the passage does not draw the conclusion that baby sea turtles can sense the magnetic field, the fact that the hatchling change their direction certainly suggests that the hatchlings are responding to changes in the magnetic field. And if the hatchlings respond to the changes, then on reasonable inference is that they are able to sense the magnetic field. So, this is the best answer.
D. Incorrect. The information in the passage about the behavior of sea turtle hatchlings in the wild deals only with their behavior as they leave their hatching grounds. It provides no support for a claim about the sea turtles\’ behavior after they have left their hatching rounds.
E. Incorrect. The passage does not provide any information that would justify an inference about the behavior of hatchlings on the coast of Africa.
*Tips and Pitfalls:
Read questions carefully. If a question asks which statement is supported by the passage, do not choose a response just because it seems on independent grounds to be plausible or likely–you must pick a response based on the information given in the passage.