posted by nina .
what this the answer for this question
We can conclude from paragraph
a)theories are often revised.
b)theories are never modified.
c)theories are always changed.
d)theories are mostly illogical.
The concept that the Earth is a sphere can be traced back 2,500 years to the Greek mathematician, Pythagoras. But how do we really know the Earth is round? The scientist does not accept authority but looks at evidence, endeavoring to see what theory, that is, what logical or mathematical description of nature best fits and explains the observations. A theory allows the scientist to make predictions about how nature might behave and suggests new observations. The experimentalist or observer examines these predictions to see if they are true. If they are, the theory stands; if not, it fails and must be modified, or a new theory must be developed to accommodate the fresh data. Although science commonly does not work in such a methodical fashion—many discoveries are quite accidental—this scientific method provides a foundation on which we can build.
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