What are the ways in which a scientific report could be biased? Explain your answer

picking certain people to be test subjects (for example if they wanted to test how people reacted to something and it was meant to mean for everyone but the only people tested were white males) or not seperating controls and having multiple factors or not taking into account a placebo effect

the purpose of a nonfiction text is to give the text a rap up. for example, when i say : frogs are interesting animals is an ending. then when i say: frogs are unique in different ways. that is an intro.