Vocabulary
Directions: Scan the following passage and find the words which have roughly the same meanings as those given below. The number in the brackets after each word definition refers to the number of paragraph in which the target word is. 

(1) George Grow Scientists say they have found two unusual amino acids in ancient rocks in Denmark. They say their findings provide support for the idea that dinosaurs died after a huge space rock hit Earth sixty-five million years ago. The idea that dinosaurs died after a space crash was proposed in 1980 by scientists at the University of California at Berkeley.
(2) Those scientists said a huge comet hit Earth at great speed. The crash created a large cloud of dust. The cloud blocked sunlight from reaching Earth. Without sunlight, Earth’s weather cooled sharply. The cold weather killed plants and other foods the dinosaurs ate. Soon, the animals were all dead.
(3) The California scientists proposed this idea after finding large amounts of the element iridium. The element was in a layer of ground formed about the time dinosaurs died. Iridium is rare on Earth. But large amounts are found in space objects such as asteroids and comets. Critics of this idea say the iridium may not have come from space. They say it could have been created by volcanoes on Earth. The latest study was headed by Jeffrey Bada and Meixun Zhao of the Scripps Institution of Oceanography in California.
(4) The scientists examined rocks from Stevns Klint in Denmark. They found large amounts of two unusual amino acids near a lager of iridium. The amino acids were in a layer formed about the same time dinosaurs died. The scientists looked for these substances in rocks from other time periods. They found none. The scientists noted that the two amino acids are found in meteorites, but are rare on Earth. The scientists said they probably did not come from Earth’s volcanoes.
(5) Surprisingly, the two amino acids found in Denmark were not found in the same layer as iridium. They were found above and below it. The scientists say the amino acids may have leaked out of the iridium layer.
(6) A separate report said there is little question that the amino acids came from space. And it said the amino acids are dated correctly. But it said more investigation is needed to link the acids with the death of dinosaurs.