Why is it necessary that only one variable be changed in an experiment,
and that all other variables remain constant?

Constant variables are variables which cannot be changed with the experiment. To remember their name is easy just think about Constance. They are important to an experiment because without all...

Explanation:

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.