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

　　(A) component

　　(B) opposite

　　(C) principle

　　(D) temperature

　　231. Since the weight of the oxygen is always added, the weight of the products of combustion, including the evolved gases, would always be greater than the weight of the starting material.

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

　　(A) later

　　(B) because

　　(C) during

　　(D) although

　　232. Iron production was revolutionized in the early eighteenth century when coke was first used instead of charcoal for refining iron ore.

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

　　(A) quickly started

　　(B) gradually opened

　　(C) dramatically changed

　　(D) carefully examined

　　233. Apart from its low cost, the appeal of iron as a building material lay in its strength, its resistance to fire, and its potential to span vast areas.

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

　　(A) adjustment

　　(B) assignment

　　(C) attraction

　　(D) attempt

　　234. Significantly, the use of exposed iron occurred mainly in the new building types spawned by the Industrial Revolution: in factories, warehouses, commercial offices, exhibition halls, and railroad stations, where its practical advantages far outweighed its lack of status.

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

　　(A) created

　　(B) maintained

　　(C) rejected

　　(D) exposed

　　235. Designers of the railroad stations of the new age explored the potential of iron, covering huge areas with spans that surpassed the great vaults of medieval hurches and cathedrals.

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

　　(A) imitated

　　(B) exceeded

　　(C) approached

　　(D) included

　　236. Their composition is thought to be similar to that of Earth's iron core, and indeed they might have once made up the core of a large planetoid that disintegrated long ago.

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

　　(A) center

　　(B) surface

　　(C) mineral

　　(D) field

　　237. When meteorites fall on the continent, they are embedded in the moving ice sheets. At places where the glaciers move upward against mountain ranges, meteorites are left exposed on the surface.

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

　　(A) isolated

　　(B) encased

　　(C) enhanced

　　(D) enlarged

　　238. The pale, smooth desert plain provides a perfect backdrop for spotting meteorites, which are usually dark brown of black.

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

　　(A) removing

　　(B) identifying

　　(C) cooling

　　(D) falling

　　239. A pioneering set of experiments has been important in the revolution in our understanding of animal behavior-a revolution that eroded the behaviorist dogma that only humans have minds.