041. The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate rocks that are semimolten at depth, and the thin, solid-surface crust.

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

(A) adapts to

(B) benefits from

(C) consists of

(D) focuses on

042. These plates move over the semimolten lower mantle to produce all of the major topographical features of the Earth. Active zones where intense deformation occurs are confined to the narrow, interconnecting boundaries of contact of the plates.

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

(A) surface

(B) sudden

(C) rare

(D) extreme

043. New oceanic crust is formed along one or more margins of each plate by material issuing from deeper layers of the Earth's crust, for example, by volcanic eruptions of lava at midocean ridges.

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

(A) edges

(B) peaks

(C) interiors

(D) distances

044. If at such a spreading contact the two plates support continents, a rift is formed that will gradually widen and become flooded by the sea. The Atlantic Ocean formed like this as the American and Afro-European plates move in opposite directions.

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

(A) separate

(B) create

(C) reduce

(D) hold

045. Coincident with concerns about the accelerating loss of species and habitats has been a growing appreciationof the importance of biological diversity, the number of species in a particular ecosystem, to the health of the Earth and human well-being.

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

(A) ignorance

(B) recognition

(C) tolerance

(D) forgiveness

046. An alien exploring Earth would probably give priority to the planet's dominant, most- distinctive feature-the ocean. Humans have a bias toward land that sometimes gets in the way of truly examining global issues.

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

(A) concern

(B) disadvantage

(C) attitude

(D) prejudice

047. The prevailing winds in the Great Basin are from the west. Warm, moist air from the Pacific Ocean is forced upward as it crosses the Sierra Nevada.

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

(A) most frequent

(B) occasional

(C) gentle

(D) most dangerous

048. There seem to have been several periods within the last tens of thousands of years when water accumulated in these basins. The rise and fall of the lakes were undoubtedly linked to the advances and retreats of the great ice sheets that covered much of the northern part of the North American continent during those times.

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

(A) dried

(B) flooded

(C) collected

(D) evaporated

049. All living creature, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?

The phrase "bizarre" is closest in meaning to which of following?

(A) odd

(B) marine

(C) simple

(D) rare

050. Its major enemies are fish and crabs, when attacked, it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attacked or even touched; it will do the same if the surrounding water temperature is too high or if the water becomes too polluted.

The phrase "casts off" is closest in meaning to which of following?

(A) grows again

(B) grabs

(C) gets rid of

(D) uses as a weapon