Using statistics.
Make a tree diagram - probability adds up to 1
Bias is when a scientist is inclined to put their own thoughts before their actual results. Therefore, an ethical scientist would not exhibit this trait.
Logic is when a scientist puts critical thinking and the scientific process first. An ethical scientist WOULD exhibit this trait.
Honesty is when a scientist tells the truth, wether or not their results align with their own thoughts/opinions. An ethical scientist WOULD exhibit this trait.
The answer to your question would be "An ethical scientist exhibits Logic and Honesty"
Most things can't be explained or it hasn't been discovered yet. Science is all about asking questions and figuring out how things are the way they are.