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science chpt. 10.
Question | Answer |
---|---|
what is a sedimentary rock? | is the type of rock that is made of harden sediment. |
what is mold? | is the hollow area in a sediment in the shape of an organism or a part of a organism. |
what is cast? | is a solid copy of the shape of an organism. |
what are a petrified fossils? | are fossils on which minerals replace all or part of an organism. |
what is a carbon film? | an extremely thin coating of carbon on rock. |
what are trace fossils? | provide evidence of the activities of ancient organisms. |
who is a paleontologist? | collect fossils from sedimentary rocks all over the world. |
what is a scientific theory? | is a well-tested concept that explains a wide range of observations. |
what is Evolution? | is the gradual change in living things over long periods of time. |
what is a relative age? | of a rock is its age compared to the ages of other rocks. |
what is a absolute age? | of a rock is the number of years since the rock formed. |
what is the law of superposition? | to determine the relative ages of sedimentary rock layers. |
what intrusion? | the magma cools and hardens into a mass of igneous rock. |
what is a unconformity? | the surface where new rock layers meet a much older rock surface beneath them. |
what is a index fossil? | Fossils of widely distributed organisms that lived during only one short period. |
what is a atom? | all the matter you see, including rocks, is made of tiny particles. |
what is an element? | when all the atoms in a particular type of matter are the same. |
what is a radioactive decay? | over time, these elements break down, or decay, by releasing particles and energy in a process. |
what is half life? | the time it takes for half of the atoms of a radioactive element to decay. |
what is a geologic time scale? | is a record of the life forms and events in Earth´s history. |
what is a era? | geologists divide the time between Precambrian Time and the present into three long unites of time. |
what are periods? | Eras are subdivided into unites of geologic time. |
what is a comet? | is a ball of dust and ice that orbits around the sun. |
what is a continental drift? | scientists have found that the continents move very slowly over Earth´s surface because of forces inside Earth. |
what are invertebrates? | Many were animals without backbones. |
what is a vertebrate? | is an animal with a backbone. |
what is a amphibian? | is an animal that lives part of its life on land and of its life in water. |
what are reptiles? | have scaly skin and lay eggs with tough leathery shells. |
what is a mass extinction? | in which many types of living things became extinct at the same time. |
what is a mammal? | is a warm-blooded vertebrate that feeds its young milk. |