Ask a question

I have a question about a practice test!! Why is the correct answer A? I choose B. It is difficult for me to understand this sentence structure.

Scientists believe that some birds navigate by use of star positions; this has been established with at least one species. In a series of studies, caged birds were subjected to the projection of the nighttime Northern Hemisphere inside a planetarium. All stars rotate around Polaris, the pole star. and this movement seemed to give the birds the information they needed to orientate themselves in the correct direction. However, some recent research contradicts this. Perhaps it is not the lack of movement of the pole star but rather the constellation patterns that guide them. It has also been found that when fewer stars were visible on the planetarium ceiling, the birds' sense of direction became poorer. And this, too, implies that the general star pattern does have some bearing on orientation.
Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A, Birds needing to orientate themselves in the right direction seemed to use the information they get from the stars that rotate around Polaris.

B, The pole star seemed to be used by birds to get the information they needed because they were able to orientate themselves using the star's rotation in the correct direction.

C, Birds needing to correct the Polaris direction in which to orientate themselves seemed to use the fact that all stars rotate.

D, The stars rotating in the correct direction around the pole star is what seemed to give the birds the information they needed for orientating themselves to Polaris.

2 Answers by Expert Tutors

Tutors, sign in to answer this question.
Tom D. | Very patient Math Expert who likes to teachVery patient Math Expert who likes to te...
The study demonstrated that they orient to the star patterns themselves and has nothing to do at all with rotation of any given star about polaris.  The new facts corroborate this.  When some constellations are taken away, they tend to fail.  They are PATTERN RECOGNIZING THE CONSTELLATIONS
I seriously doubt birds track movement of stars since it occurs very slowly.  Even we don't do this.  We see a constellation and can navigate off this semi-fixed position for reasonably short periods of time (<30min).


Thank you, Tom!!
They are pattern recognizing the CONSTELLATIONS!!
The facts shows this, right?
Thank you again!!
Yes - correct.  When we drive at night, we may see perhaps the big dipper and we can steer in that direction. This is a very good compass for short durations.  Of course that star field moves as the earth rotates on its axis.  It is identical to steering into the Sun.  It works for awhile, but only for awhile.  Imagine steering toward the sun all day.  First you are driving East and at the end of the day, you are driving West.  That's a function of longitude&Lattitude, but don't worry about that.
Birds probably use constellations as short-term beacons.  The article doesn't mention it, but they might realize that those beacons are moving just as you & I know that they move.
Naina B. | Naina, a versatile tutorNaina, a versatile tutor
4.8 4.8 (155 lesson ratings) (155)
Hi Saori,
I think that the correct answer is A for following reasons:
1. The highlighted sentence says that all stars rotate around Polaris star and this movement  seemed to give the birds the information they needed to orientate themselves in the correct direction.  Here the movement implies to the movement of all other stars that rotate around Polaris. It does not imply to the movement of pole star itself.
2. The statement A refers exactly to the information implied in highlighted sentence; it says  that birds get the information to orient themselves in right direction from the stars that rotate around Polaris.
3. The statement B says that birds use the information from  Pole star and this star's rotation to orient themselves in the right direction. However, the highlighted sentence says that birds use the information from the movement of the stars that rotate around Polaris. It does not say that rotation of Polaris star gives direction to birds as it is  given in statement B.
Therefore, statement A is correct answer and statement B  is not.