Help I'm in a Japanese airport what does this word mean > ( 長距離旅行 )

Which best summarizes what scientists learned about how microbes benefit the human body? they are part of a normal human ecosystem. they have become less harmful to humans than they used to be. they process nutrients, fight disease, and accommodate change. they humans overcome the effects of antibiotics.`

Ispeak italian.. c'è qualcuno di italiano qua?

Iknow why the cage bird sings, how does the autjor’s decision to include the underlined action impact the readers understanding