This photograph shows the law crosscutting. What is the law of crosscutting?
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A fault or intrusion of rock younger than the rock it cuts through.
In undisturbed rock layers, the older rocks are on the bottom and the younger rocks are on the top.
The law of crosscutting states that a fault or intrusion of rock is younger than the rock it cuts through. In other words, if a fault or intrusion is found cutting across existing rock layers, the fault or intrusion must have occurred after the formation of the rock layers it cuts through. This principle helps geologists determine the relative ages of geological features.
The law of superposition uses relative age to determine the age of rocks and fossils. What is absolute age?
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The age of a rock or fossil compared to the rocks or fossils around it.
The age of a fossil or rock expressed in actual years.
The correct answer is: The age of a fossil or rock expressed in actual years. Absolute age refers to the exact age of a rock or fossil, typically determined through various dating methods that involve measuring the decay of specific isotopes or analyzing rock layers. Relative age, on the other hand, is determined by comparing the age of a rock or fossil to the ages of other rocks or fossils around it.
Carbon dating uses an isotope of the element carbon. The most common form of carbon has 6 protons and 6 neutrons. It is called carbon-12. Carbon-14 is an isotope of carbon that has 8 neutrons. The extra neutrons make carbon-14 unstable, or radioactive. Atoms that are unstable tend to break apart. This process is called radioactive decay. All living organisms contain carbon. Plants get carbon from the atmosphere. Animals get carbon from food. Most of the carbon is carbon-12, but some of it is carbon-14. Carbon cycles through living things while they are alive. The ratio of carbon-12 to carbon-14 remains the same while a plant or animal is alive. When the plant or animal dies, the carbon-14 begins to decay. By comparing the ratio of carbon-12 to carbon-14, scientists can tell how long the plant or animal has been dead. To determine the absolute age of rocks and fossils, scientists use:
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The difference between the amounts of carbon-12 and carbon-14.
The ratio between carbon-12 and carbon-14
The difference between the number of protons and neutrons in carbon-14.
This photograph shows a mold fossil. How is a mold fossil different from a cast fossil?
The correct answer is: The ratio between carbon-12 and carbon-14. To determine the absolute age of rocks and fossils, scientists use the ratio of carbon-12 to carbon-14. As explained in the passage, the ratio of these isotopes remains the same while a plant or animal is alive. However, after death, the carbon-14 starts to decay, allowing scientists to measure the remaining ratio and calculate the time since the organism's death.
Regarding your second question, a mold fossil and a cast fossil are different in terms of their formation and characteristics. A mold fossil forms when the hard parts of an organism, such as bones or shells, dissolve or decay, leaving behind an imprint or hollow space in the surrounding sediment. On the other hand, a cast fossil forms when a mold is filled with minerals, creating a replica of the original organism.
To summarize, a mold fossil represents the impression or negative space left by the decayed organism, while a cast fossil is a replica or positive form created by the filling of a mold.
This photograph shows a mold fossil. How is a mold fossil different from a cast fossil?
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A cast fossil is a depression in rock or soil made by the hard parts of organisms. A mold fossil is a cast fossil that becomes filled in with minerals in the shape of the cast.
A mold fossil is a depression in rock or soil made by the hard parts of organisms. A cast fossil is a mold fossil that becomes filled in with minerals in the shape of the mold.
The correct answer is: A mold fossil is a depression in rock or soil made by the hard parts of organisms. A cast fossil is a mold fossil that becomes filled in with minerals in the shape of the mold.
In a mold fossil, the original organism decays or dissolves, leaving behind an empty space or indentation in the rock or sediment. The mold represents the negative space where the organism once existed. A cast fossil is formed when this mold is filled in with minerals, creating a replica or positive form of the original organism. The minerals fill the mold and harden, preserving the shape and details of the organism.