These are preparation questions for the DNS lab. You need a score of 80% or more in order to do the lab.
You can try as many times as you like, there is no restriction on the number of attempts. Before you can be allowed to do the lab, you need to show your answers to the lab assistants.
To answer the questions, you may want to consult other sources besides the course textbook. In particular, the BIND manual and the Wikipedia pages about zone files and DNS are useful.
The questions primarily covers the format of zone files, DNS records, and some basics of the DNS protocol. Take your time and answer the questions carefully; it will make the lab easier.