What is another word for something that is okay to do, but not required?

I’m your response, discuss how this part of the speech fits into the overall structure of the text and analyze how well it’s supports the authors overall purpose.

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 opening stanza portray a frightened narrator fleeing though darkness. how does it rhythm reflect and enhance its meaning