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passage 3
This passage was adapted from an article published in 2000.
P1
Problem ·
Computer chips will hit a point where they can't be made any smaller
With current methods, transistors (devices that make up computer chips) cannot be made smaller than 25 nanometers.
Potential solution ·
Natural chemical processes might produce smaller molecules that act like transistors
Belcher and Hu ·
B and H are investigating peptides
Others are researching DNA to try to create small transistor-like molecules. B and H are researching something else -- peptides.
P2
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Background leading to research ·
Arose from research that found peptides could cause calcium carbonate to form structure found in abalone shell
B and H thought peptides might create crystalline structures associated with transistors.
B and H's research ·
Grew a billion different peptides, found that some can bind to semiconductor materials
P3
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Future research ·
Identifying additional organic compounds that can bind to additional semiconductor mateirals
Passage Style
Problem-analysis
Single position
18.
Which one of the following ██████████ █████ ███ ████████ ████ ███████ ███ ██ ██████ ██ ████████ ██ ██████████████ ███ ██ ████ ██████████ ████████ ████ ███ ████████
a
At least some ██ ████ ███ ███ ██████████ █████ ██ ███████
b
At least one ██ ████ ███ █████ ██ ████ ██ █████ █████████ █████████████ ██████████
c
At least some ██ ████ ████ ██████ ██ ████████ ██ ███████ ███ ███ ██ ████████ ██ ███████ █████████
d
At least one ██ ████ ███ ██ ███ ██ ███ ████████ ████ ████████ █████ ██ ███████ ███ ████ █████████
e
Other researchers had ██████████ ██████ ██ █████ ████ ██ ████ ███ ████████ █████████ ████ █████████████ █████████ █████ ████ ████████ ███████ █████████ ███ ██████ ██████████