In a nutshell, Uriel is a fictional planet in Madeleine L'Engle's sci-fi/fantasy book A Wrinkle in Time… 'the third planet of the star Malak in the spiral nebula Messier 101,' to quote the book exactly. It is a beautiful and peaceful planet, inhabited by beautiful and peaceful creatures.
On the way to rescue Dr. Murry, Meg, Charles Wallace, and Calvin make a pit stop on Uriel. The purpose for this pit stop, according to Mrs. Whatsit, is 'more or less to catch our breaths. And to give you (the children) a chance to know what you're up against.'
To fully understand this planet and its role in the story, a little background knowledge is important.
“Did you know that harnesses are far more secure than dog collars? Dog collars are in fact dangerous in some cases, causing harm to dogs necks, and dogs can slip out!”
The answer would be a references page.
B - Down. Just try and see if it makes sense to be in the sentence