Can some one please help me

Im the following sentence, what is the complete subject . an old friend of mine is in the hospital

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?

Does anyone know the answers to these two? i don’t want to have to guess, you!