Answer:
A fair test.
Explanation:
Hi, a fair test is used to do scientifically valuable experiments, is a controlled investigation to answer a scientific question.
In a fair test two or more things are compared.
It consists in changing only one factor (the one bieng tested) and keeping all the other conditions the same during an experiment.
The factor is called a variable.
Tycho Brahe ( 1546 - 1601 ) was a Danish astronomer known for his accurate astronomical and planetary observations. Tycho tried to produce a model with the best of both Ptolemy ( earth-centered solar system ) and Copernicus ( sun-centered solar system ).
Answer: B ) observation.
It’s the engery. you are changing the engery
