Recent discoveries of microscopic fossils have extended the known history of life to about:
A. 1 billion years ago.
B. 2 billion years ago.
C. 3.5 billion years ago.
D. 4.5 billion years ago.
C. 3.5 billion years ago.
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The half-life of carbon-14 is 5,600 years. A fossil that has one-eighth the normal proportion of carbon-14 to carbon-12 is probably
A. 2,800 years old. B. 5,600 years old. C. 11,200 years old. D. 16,800 years old. E. 22,400 years old. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about half-lives of radioactive isotopes? What other information is related to the question? Choose Answer Given what you now know, what information is most likely to produce the correct answer? Reflect on Process Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
The Human Genome Project was started in 1986 to
a. identify the nucleotide sequences of all human genes. b. develop a complete DNA library for a human gene. c. develop genetic markers for all genetic diseases. d. catalog all the varieties of human alleles. e. identify all humans that possess genetic defects.
Over many generations, the population of snakes should evolve toward striped snakes that flee by turning or checkered snakes that flee straight.
a. true b. false
The ________ approach to gene cloning employs a mixture of fragments from the entire genome of an organism and results in the production of thousands of different recombinant plasmids
A) shotgun B) genetic engineering C) restriction D) cloning