1. What is the boldfaced word?
2, 3, 5, 6, 7, and 8.Sorry, I'm not sure what the answers to those are.
4 and 9. See #1.
10. The bark of cork trees HAS many commercial uses.
This is because the verb must agree with the subject. The subject of this
sentence is bark. "of cork trees" is a prepositional phrase. If it helps you
to put parenthesis (mentally or physically) around prepositional phrases
before trying to figure out which verb is correct, do so.
11. Both cats and monkeys HAVE tear ducts.
This is because cats and monkeys are plural, and again, there must be
subject-verb agreement.
12. In the Blue Ride Mountains ARE many summer camps.
This is because the word "Mountains" is plural.
Hope this helped :)