plummets, the ice contracts. In the reverse process, when this very cold ice finally melts, it must expand a second time, pushing the stone once more.
In theory, the upward movement of fieldstones should result in pure soil, all the stones above the frost line having been pushed to the surface and carried away. What a vision! Acres of pure, deep soil and crowbars rusting away unused. Alas, the fastest stones move only an inch or so a year, and most are orders of magnitude slower. 1. What does the passage mainly discuss? (A) The effect of frost heaving on stones (B) The water content of various types of soil (C) Factors affecting the rate of ice expansion (D) Seasonal variations in ground temperature 2. What statement was most probably made in the paragraph preceding this pasage? (A) Pure soil is quickly eroded.
(B) Fieldstones are lifted to the top of the soil. (C) It is not easy to move stones from fields.
(D) Ancient cultural artifacts are buried deep in the soil. 3. Where does the soil freeze first in the fall? (A) On the tops of stones (B) In areas of pure, deep soil (C) Under rocks (D) On islands 4. In the first paragraph, the author gives an example of (A) glacier movement (B) soil erosion (C) climate change (D) heat conduction 5. According to the passage, why do fieldstones remain raised in the soil when the ice thaws? (A) Melting ice erodes the soil around them. (B) Soil fills in under them
(C) They remain in a frozen layer of topsoil.
(D) The frost line under which they are resting moves upward. 6. The author refers to a car jack in an analogy that illustrates how (A) stones are pushed upward
(B) heavy rocks press down on deep levels of soil (C) a crowbar is used to remove stones from soil (D) automobile parts freeze in cold weather 7. Which of the following conclusions is supported by the third paragraph? (A) Stones above the frost line will quickly be pushed upward. (B) The number of stones surfacing each year is decreasing. (C) Acres of pure, deep soil regularly result from frost heaving. (D) New stones will continue indefinitely to surface at a slow rate. 8. In line14, the author exclaims \(A) fear (B) disgust (C) enthusiasm (D) romance
Passage 8
A summary of the physical and chemical nature of life must begin, not on the Earth, but in the Sun; in fact, at the Sun's very center. It is here that is to be found the source of the energy that the Sun constantly pours out into space as light and heat. This energy is liberated at the center of the Sun as billions upon billions of nuclei of hydrogen atoms collide with each other and fuse together to form nuclei of helium, and, in doing so, release some of the energy that is stored in the nuclei of atoms. The output of light and heat of the Sun requires that some 600 million tons of hydrogen be converted into helium in the Sun every second. This the Sun has been doing for several thousands of millions of years.
The nuclear energy is released at the Sun's center as high-energy gamma radiation, a form of electromagnetic radiation like light and radio waves, only of very much shorter wavelength. This gamma radiation is absorbed by atoms inside the Sun, to be re-emitted at slightly longer
wavelengths. This radiation, in its turn, is absorbed and re-emitted. As the energy filters through the layers of the solar interior, it passes through the x-ray part of the spectrum, eventually
becoming light. At this stage, it has reached what we call the solar surface, and can escape into space, without being absorbed further by solar atoms. Avery small fraction of the Sun's light and heat is emitted in such directions that, after passing unhindered through interplanetary space, it hits the Earth. 1. What does the passage mainly discuss? (A) the production of solar light and heat (B) the physical and chemical nature of life (C) The conversion of hydrogen to helium (D) Radiation in the x-ray part of the spectrum 2. According to the passage, energy is released in the Sun when (A) helium atoms bind with each other
(B) gamma radiation escapes from the spectrum (C) radiation is absorbed by helium (D) nuclei of hydrogen atoms collide 3. The passage indicates that, in comparison to radio waves, gamma waves (A) produce louder sound (B) are less magnetic
(C) do not form in the Sun's center (D) are not as long 4. According to the passage, through which of the following does the energy released in the Sun
pass before it becomes light? (A) The x-ray part of the spectrum (B) Electromagnetic space (C) The solar surface (D) Interplanetary space 5. It can be inferred from the passage that the Sun's light travels (A) through solid objects in space (B) in many different directions
(C) more slowly than scientists previously believed (D) further in summer than in winter
