The answer to this question is Bias
When researchers are being biased in their analysis, all of their analysis become really unreliable because it does not fully reflect to the truth.
To make the result of the researchers fully reliable, researchers need to base their analysis solely to the data at hand
The reason why Russia is spoken by a lot of these countries is because Many of these countries use to be part of the Soviet Union.
<h3>What was the Soviet Union?</h3>
This was a socialist and communist republic that existed in Europe for a period of 69 years.
The people had a similar language at the time before it was dissolved in the year 1991.
Read more on the Soviet union here: brainly.com/question/1310325