Yes, you can, but you can only share one screen with your Participants at a time. Also, once you select to share your screen, Participants and Host’s video will automatically drop to smaller windows/blocks. You can also monitor the Chat and Management for Participants windows on your primary screen. Read more about Can I use Zoom application with multiple screens?
A new term, "Zoom Bombing," is when people who have not been invited enter Zoom meetings to cause disruption. Such disruptions can be mild, or as we've seen elsewhere, can include racist, hate, or pornographic material. Here are some tips to alleviate this issue.
Judicious Sharing of Meeting Info: Do not share the Meeting Link or ID on open platforms where anyone but the intended audience can see them.
Yes, Zoom has toll numbers available for all plans. Please check out this article for more information. However, you may be charged for these calls and it is recmmended you attempt to sign in via an internet connect first.