501 Critical Reading Questions

a.
cementum.
b.
dentine.
c.
dahllite.
d.
ameloblasts.
e.
collagen.
389.
According to the passage, how can natural ivory be authenticated?
a.
by ultraviolet light
b.
by gamma rays
c.
by physical observation
d.
by osmosis
e.
by scrimshaw
390.
According to the passage, which statement is NOT true of
enamel?
a.
It is an organic substance.
b.
It is the hardest of animal tissues.
c.
It should never be exposed to ultraviolet light.
d.
It structure is prismatic.
e.
It is formed with the aid of ameloblasts.
501
Critical Reading Questions

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Questions 391–399 are based on the following passage.
This passage is about the process by which scientists prove theories, the
scientific method.
The scientific method usually refers to either a series or a collection
of processes that are considered characteristic of scientific investiga-
tion and of the acquisition of new scientific knowledge.
The essential elements of the scientific method are:
Observe:
Observe or read about a phenomenon.
Hypothesize:
Wonder about your observations, and invent a
hypothesis, or a guess, which could explain the phenomenon or
set of facts that you have observed.
Test: 
Conduct tests to try out your hypothesis.
Predict:
Use the logical consequences of your hypothesis to pre-
dict observations of new phenomena or results of new 
measurements.
Experiment:
Perform experiments to test the accuracy of these
predictions.
Conclude:
Accept or refute your hypothesis.
Evaluate:
Search for other possible explanations of the result until
you can show that your guess was indeed the explanation, with
confidence.
Formulate new hypothesis:
as required.
This idealized process is often misinterpreted as applying to scien-
tists individually rather than to the scientific enterprise as a whole. Sci-
ence is a social activity, and one scientist’s theory or proposal cannot
become accepted unless it has been published, peer reviewed, criti-
cized, and finally accepted by the scientific community.
Observation
The  scientific  method  begins  with  observation.  Observation  often
demands careful 
measurement
. It also requires the establishment of  an
operational definition 
of measurements and other concepts before the
experiment begins.
Hypothesis
To explain the observation, scientists use whatever they can (their
own creativity, ideas from other fields, or even systematic guessing)
to come up with possible explanations for the phenomenon under
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501