Which of the following statements is the writer most likely to agree with?

1. Bird formations vary in accordance with the bird species.
2. There is positive proof for the theories of bird formation and the position of bird within it
3. Energy conservation seems to be the overarching single factor behind bird formations during all flights.

   PASSAGE – I
   The passage below is followed by a question based on its content. Answer the question on the basis of what is stated or implied in the passage.

   Migratory birds often move in linear flight formations called echelons. Typically, we find V and J-type structures, which are the most readily recognized flock echelons, nevertheless other variations to these major patterns can also be found. A true V-shaped echelon is, in reality, less common than a J formation, studies conducted on several species reveal.
   Why do the birds fly in formations? Two well-corroborated and complementary explanations are available right now. A major idea is to save energy by capitalizing on the upwash vortex fields generated by the bird wings in the front. The second - to facilitate the job of orientation and communication among the flying birds. These two explanations are not necessarily mutually exclusive, and in fact, both are supported by many studies. The relative importance of each of them, no doubt, changes as various factors, like the season of the year or the reason behind  individual flights, change. During local feeding flights meant to locate food, for instance, careful orientation and collision avoidance are probably much more important than the conservation of energy. However, during long-distance migration, though orientation and communication remain important, but the case for conservation of energy by optimization of its position holds greater importance for each bird in the flock.

   Where should the birds position themselves in relation to others to conserve the most energy as they fly in the air? Fluid dynamics and energy wave configuration calculations supply the answer. Analysts, using photography, have determined bird positions and found them to almost always be located to enable the bird to earn some energetic advantage. However, the birds are not always at the expected optimal location, indicating that other factors also come into play.

   Researchers have used the knowledge of birds, visual axes, "blind spots" and visual fields to pinpoint the best locations for a bird in a flock to maintain optimal visual positioning. The actual positions are usually having a positive correlation with these predictions but are, again, not always perfect. The positions of birds have been classified and it has been found that some individuals occupy positions to satisfy the energy conservation principle; others enjoy better visual contact placement, while the rest do not apparently respond to either benefit or are in a position so as to gain some advantage from both the benefits available.

   The leaders of these bird formations change with time, but it has not been possible to discover the causes, frequency and characteristics associated with these changes. Observations on a sustained basis of such flocks covering long distances in the air are very difficult. Several intuitive predictions about the choice of the formation leader that immediately come to mind are - age, experience, sex, condition and social status of the leaders, but so far researchers have been unable to overcome the logistic issues to put these hypotheses to test. Birds have been trained to fly in formation with small aircraft by some scientists; possibly their efforts will yield opportunities to test these hypotheses.