A. radioactive implosion B. Nuclear Fission C. nuclear fusionD. combustion
ANSWER: B Nuclear fusion is the process by which two or more nuclei with small masses (such as hydrogen) join together, or fuse, to form a larger, more massive nucleus (such as helium). During this process, a massive amount of energy and radioactive emissions (such as gamma rays) are produced. Combustion, and even nuclear fission, would consume too much matter, causing a star to die much too quickly.
A. a globular cluster B. A retrograde pattern C. A constellation D. A nebula
Answer: C Constellations helped astronomers in the sciences early history to organize the sky and track the apparent motions of planets and stars. Commonly recognized constellations include the Big Dipper, the Little Dipper, Ursa Major, and so forth.
A. From the planets in a solar system B. In comets C. In asteroids D. In nebulae
Answer: D A nebula is a large cloud of gas and dust spread out in an immense volume. Stars are formed from the gas and dust of a nebula.
A. Gravitation B. Friction C. Magnetism D. Electromagnetic energy
Answer: B The core is at the center of the sun. This is where the suns energy is produced through the process of nuclear fusion of hydrogen atoms.
A. A galaxy B. A quasar C. A pulsar D. A nebula
Answer: A A galaxy is a huge grouping of individual stars, star systems, star clusters, dust, and gas all bound together by gravity. There are billions of galaxies in the universe, each containing billions or even trillions of stars.
A. Irregular galaxy B. Spiral galaxy C. Elliptical galaxy D. Spherical galaxy
Answer: B Galaxies that appear to have a bulge in the middle and arms that spiral outward are known as spiral galaxies. Most galaxies, including the Milky Way are spiral galaxies.
A. A theory that states that the universe began with a tremendous explosion. B. A theory that states that particles in the universe are constantly imploding. C. A theory that states that the universe has no beginning and no end. D. A theory that states that the universe is currently nothing more than a small ball of matter.
Answer: A Astronomers theorize that the universe was first formed 10 to 15 billion years ago. At that time, all of the matter in the universe was melded together into an incredibly dense ball that was no more than a millimeter or so in diameter. The ball then exploded in what is known as the big bang.
A. Fossil correlation B. Radiometric analysis C. Absolute dating D. Rock ordering
Answer: A Fossil correlation is used to reconstruct the history of life on Earth. Although the rock types vary from outcrop to outcrop, the sedimentary rock layers contain fossils, called index fossils, that mark a specific moment in geologic history. Index fossils are used to correlate the fossils in one area with fossils in another area.
A. Fungi B. Archaebacteria C. Protista D. Eubacteria
Answer: C Today, eukaryotes are single- or multi-celled organisms, but the first eukaryotes were only single-celled. They were differentiated from prokaryotes by their nucleus. These nucleus- bearing, single-celled organisms were the ancestors of modern-day protists (as well as all other forms of eukaryotic life).
A. The development of the nucleus B. Endosymbiosis C. Cell differentiation D. The evolution of organelles
Answer: C A unicellular organism must carry out all of the activities of the organism within the structures of a single cell. Distinct types of cells in one body can have specialized functions in a multicellular organism. Therefore, the development of the ability of a cell to become differentiated led to the evolution of multicellular life forms.
A. Potassium-argon method B. Uranium-lead method C. There is no radiometric dating method available for an object of that age. D. Carbon-14 method
Answer: D The half-life of uranium-238 is 4.5 billion years. The half-life of potassium-40 is 1.3 billion years. The half life of carbon-14 is 5,730 years. Therefore, the carbon-14 method would be adequate to date an object that was around 20,000 years old.
Answer: C There is only a limited amount of silver on Earth. Once all the silver has been used up, no more can be made. Resources such as trees, however, can be planted and grown to replace the ones we use, and resources such as sunlight and wind are extremely abundant and will constantly be renewed as long as our solar systems sun burns.
A. Millions of years B. Billions of years C. Hundreds of years D. Thousands of years
Answer: B It takes millions of years for fossil fuels to form. As a matter of fact, the majority of the fossil fuels we use today were formed around 300 million years ago.
A. Petroleum B. Iron ore C. Fresh water D. Diamonds
Answer: C Some communities have a hard time providing enough fresh water for everybody, but because fresh water is constantly recycled in the environment through the water cycle, freshwater can still be considered a renewable resource. The other resources listed will someday run out if we keep using them, so we must learn to conserve, or limit our use.