Answer:
Answer
+ 5.0
Answer: The NEGATIVE CONTROL is the
test tube that is filled with ONLY distilled
water.
Explanation:
A negative control of an experiment is
carried out alongside the main primary
experiment except that the treatment is
changed to something that is predicted
to have no result. In the negative
control, the student does not expect any
response. This would help the student
compare the result of a new experiment
against an already known existing results.
Analysing the experiment carried out
by the student, She filled two test tubes
with distilled water and placed a piece
of Elodea in one of the tubes, leaving
the other without a plant. The other test
tube that contains only distilled water is
the negative control because she wasn't
expecting any result from it. It's also
served as a control sample to the primary
experiment. This is observed as she
blew in each tube to add carbon dioxide,
which caused the distilled water to
become more acidic. This would help the
student know that the that experimental
results are valid and to ensure that time is
saved
