Answer:
1. Dion noticed that the campsite location was obscure (remote). - synonym clue
2. Pia couldn't wait to visit the menagerie—the place where the animals were kept. - definition clue
3. Unlike her last dog, who didn't know the meaning of loyalty, Violet's new dog is a staunch friend. - antonym clue
Explanation:
In sentence 1, we are literally given the synonym of the word in parentheses. The author guesses the word "obscure" might be unknown to some readers and decides to offer another word that carries the same meaning as it - a synonym - to help clarify. That is why the word "remote" is added right after "obscure".
In sentence 2, the author chose to define or explain the word "menagerie", almost like a dictionary would. He/she adds a dash after the word to then include the definition. We now know that a menagerie is the place where animals were kept.
Finally, in sentence 3, we can figure out the meaning of "staunch" by comparing it to the word "loyalty". Two dogs are being compared. One does not understand loyalty. The other one, however, is staunch. We can safely assume the latter is loyal, faithful, because of such a comparison. What the author did here was use words that have opposite meanings - antonyms - to reveal the meaning of the unknown word.