How are the characters in Stockon's and Checkhov's the same?

Read the passage: canines may not be the deepest thinkers in the world. but perhaps that's for the best. the life of a dog—sitting alone all day, waiting for everyone to come home—can be pretty boring. super-smart animals would probably get totally stressed out, says university of pennsylvania researcher james serpell. look at it this way: if dogs were any smarter, they probably wouldn't choose to hang around with us. which best describes the tone of the passage?

The owners reputations are in jeopardy.

Which would be the most credible source for researching the effects of smoking? letter from your grandfather web page about someone’s lung cancer report prepared by a tobacco company research article in a scientific journal