261. It dissolves, transports, and precipitates many chemical compounds and is constantly modifying the face of the Earth. Evaporated from the oceans, water vapor forms clouds, some of which are transported by wind over the continents.

　　The word "modifying" is closest in meaning to which of following?

　　(A) changing

　　(B) traveling

　　(C) describing

　　(D) destroying

　　262. This last figure shows the importance of the ocean as the principal reservoir of the hydrosphere but also the rapidity of water transport on the continents.

　　The word "rapidity" is closest in meaning to which of following?

　　(A) significance

　　(B) method

　　(C) swiftness

　　(D) reliability

　　263. The erosion of the continents thus results from two closely linked and interdependent processes, chemical erosion and mechanical erosion. Their respective interactions and efficiency depend on different factors.

　　The word "efficiency" is closest in meaning to which of following?

　　(A) relationship

　　(B) growth

　　(C) influence

　　(D) effectiveness

　　264. Among the species of seabirds that use the windswept cliffs of the Atlantic coast of Canada in the summer to mate, lay eggs, and rear their young are common murres, Atlantic puffins, black-legged kittiwakes, and northern gannets.

　　The word "rear" is closest in meaning to which of following?

　　(A) visit

　　(B) watch

　　(C) reverse

　　(D) raise

　　265. The advantage of nesting on cliffs is the immunity it gives from foxes, which cannot scale the sheer rocks, and from ravens and other species of gulls, which have difficulty in landing on narrow ledges to steal eggs.

　　The word "scale" is closest in meaning to which of following?

　　(A) climb

　　(B) avoid

　　(C) approach

　　(D) measure

　　266. This immunity has been followed by a relaxation of the defenses, and kittiwakes do not react to predators nearly as fiercely as do ground-nesting gulls.

　　The word "immunity" is closest in meaning to which of following?

　　(A) distance

　　(B) transition

　　(C) protection

　　(D) reminder

　　267. Kittiwakes defecate over the edge of the nest, which keeps it clean, but this practice, as well as their tendency to leave the nest littered with eggshells, makes its location very conspicuous.

　　The word "conspicuous" is closest in meaning to which of following?

　　(A) disordered

　　(B) suspicious

　　(C) noticeable

　　(D) appealing

　　268. On the other hand, nesting on a narrow ledge has its own peculiar problems, and kittiwake behavior has become adapted to overcome them.

　　The phrase "On the other hand " is closest in meaning to which of following?

　　(A) therefore

　　(B) however

　　(C) for example

　　(D) by no means

　　269. Throughout the nineteenth century and into the twentieth, citizens of the United States maintained a bias against big cities.

　　The word "bias" is closest in meaning to which of following?

　　(A) diagonal

　　(B) slope