Q1 - Sea turtle hatchlings leaving

[sumukh09]

This is a most strongly support question so we're looking for something that we can prove within the confines of the stimulus. This question gives us a series of facts about sea turtle hatchlings and how they reach ocean currents. The hatchlings swim to the northeast and that's how they reach ocean currents, but there's more to be discerned about how it is they go about this swimming process. The earth's magnetic field influences where the hatchlings swim to, however when surrounded by an artificial magnetic field that is twice as strong as the earth's magnetic field the hatchlings swim in an opposite direction.

Answer choices:

A) Way out of scope - open sea? join groups of adults?

B) This one was tempting and admittedly I fell for this trap answer choice as I was enticed by the "as defined by the north of the Earth's magnetic field" part of the stimulus. This A/C is wrong however because we have no idea how the direction of ocean currents is affected by the earth's magnetic field and so this is unsupported.

C) This is the correct answer. We can find support for this because the last sentence says that the hatchlings swim in the opposite direction when an artificial magnetic field is present. Therefore, if they can sense that the magnetic field is artificial then that must mean they can also sense the magnetic field of the earth since they do NOT swim in the opposite direction in the absence of an artificial magnetic field.

D) Unsupported - we have nothing in the stimulus that talks about the return of the sea turtles

E) Way out of scope

[rinagoldfield]

Awesome job, Sumokh09! I agree with your takedown of all the wrong answer choices _ nice work.

I have a slightly different take on the correct answer, C. We can’t infer that the hatchlings know whether a magnetic field is artificial or natural.

Rather, we know that the hatchlings swim towards the magnetic north. They swim north in the ocean. They swim north in a tank. They swim south when surrounded by an artificial magnetic field whose direction is the opposite of the Earth’s. In other words, the artificial field’s magnetic south is like the Earth’s magnetic north. Surrounded by the artificial magnetic field, the baby turtles swim the direction that seems north to them.

This strong northern inclination implies that baby turtles can sense magnetic fields, and know to swim towards the field’s northern pole.