It can reasonably be inferred from passage 1 that, for most bird
species, there is a certain size at which they

If Passage 1 is adapted from "Ancient DNA Tells Story of Giant Eagle  

Evolution," © 2005 by Public Library of Science, then the answer would be as follows:

It can reasonably be inferred from Passage 1 that, for most bird species, there is a certain size at which they  

a.are unable to fly.

Explanation:

According to Passage 1, "When the dodo's ancestor (thought to be a migratory pigeon) settled on this island with  abundant food, no competition from terrestrial mammals, and no predators, it could survive without flying, and thus was freed from the energetic and size constraints of flight. "

"Size constraints of flight" means that the birds that are big to a certain size cannot/could not fly. Taking examples of some birds once roaming New Zealand into consideration, they were giant birds with large wingspans, and therefore, they were unable to fly (flightless).

Other options, namely b. require less energy when flying; c.are more likely to attack other animals; and d.do have a to compete with other birds for food, are nowhere found in Passage 1. In other words, No related information is available.

Therefore, the most possible answer is a.

bought and considered

source text: from the sketch here given it will be seen, that our good grandmothers differed considerably in their ideas of a fine figure, from their scantily dressed descendants of the present day. a fine lady, in those times, waddled under more clothes even on a fair summer's day, than would have clad the whole bevy of a modern ball room. nor were they the less admired by the gentlemen in consequence thereof. on the contrary, the greatness of a lover's passion seemed to increase in proportion to the magnitude of its object—and a voluminous damsel, arrayed in a dozen of petticoats, was declared by a low-dutch sonnetteer of the province, to be radiant as a sunflower, and luxuriant as a full blown cabbage. certain it is, that in those days, the heart of a lover could not contain more than one lady at a time; whereas the heart of a modern gallant has often room enough to accommodate half a dozen - - the reason of which i conclude to be, either that the hearts of the gentlemen have grown larger, or the persons of the ladies smaller — this however is a question for physiologists to determine. add punctuation to the following excerpt. writing under the name of diedrich knickerbocker washington irving aimed his potent satire at as diverse topics as political rivals such as thomas jefferson to the very ideal of looking back on the past affectionately: a fine lady, in those times, waddled under more clothes even on a fair summer's day, than would have clad the whole bevy of a modern ball room. a voluminous damsel, arrayed in a dozen of petticoats, was declared by a low-dutch sonnetteer of the province, to be radiant as a sunflower, and luxuriant as a full blown cabbage. in those days, the heart of a lover could not contain more than one lady at a time; whereas the heart of a modern gallant has often room enough to accommodate half a dozen