Chapter 2: Q2.2-2ITD (page 33)
Recall that 14C has a half life of 5,730 years. To calibrate the x-axis for 14C decay, write the time before present in years below each half-life.
Chapter 2: Q2.2-2ITD (page 33)
Recall that 14C has a half life of 5,730 years. To calibrate the x-axis for 14C decay, write the time before present in years below each half-life.
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Get started for freeWhich statement is true of all atoms that are anions?
(A) The atoms have more electrons than protons.
(B) The atom has more protons than electrons.
(C) The atom has fewer protons than does a neutral atom of thesame element.
(D) The atom has more neutrons than protons.
The percentage of naturally occurring elements making up the human body (see table2.1) is similar to the percentage of these elements found in other organisms. How could you account for this similarity among organisms?
In the term trace element, the adjective trace means that
(A) the element is required in very small amounts.
(B) the element can be used as a label to trace atoms through an organismโs metabolism.
(C) the element is very rare on Earth.
(D) the element enhances health but is not essential for the organismโs long-term survival.
Carbon-14 dating works for fossils up to about 75,000 years old; fossils older than that contain too little 14C to be detected. Most dinosaurs went extinct 65.5 million years ago. (a) Can 14C be used to date dinosaur bones? Explain. (b) Radioactive uranium-235 has a half-life of 704 million years. If it was incorporated into dinosaur bones, could it be used to date the dinosaur fossils? Explain.
The researchers found that the Neanderthal fossil had approximately 0.0078 as much 14C as found originally in the atmosphere. (a) Using the numbers on your graph, determine how many half-lives have passed since the Neanderthal died. (b) Using your 14C calibration on the x-axis, what is the approximate age of the Neanderthal fossil in years (round off to the nearest thousand)? (c) Approximately when did Neanderthals become extinct according to this study? (d) The researchers cite evidence that modern humans (H. sapiens) became established in the same region as the last Neanderthals approximately 39,000 โ 42,000 years ago. What does this suggest about the overlap of Neanderthals and modern humans?
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