Why does the author of the call of the wild describe buck's progress as "retrogression"?

Buck was returning to his ancient instinctual roots is the answer.

Explanation:

the Call of the Wild is a book written by Jack London, an American writer and journalist. The question refers to the main character, Buck, which was a dog taken to Alaska after he is stolen from his home in California. The speaker considers Buck's progress as a retrogression because he was coming back to his feral instincts in order to survive in such hard conditions as a sled dog.

the sentence that contains a restrictive clause is a.they decided to meet where the band was performing

explanation:

a restrictive clause is also known as an essential clause