What kind of clause the meeting cannot start until the moderator arrives?

This is a complex sentence.

A complex sentence contains one independent clause and at least one dependent clause (although there may be more than one). In the sentence above, the independent clause is The meeting cannot start and the dependent clause is until the moderator arrives.

A dependent clause cannot stand on its own - it has to be part of a larger, independent clause.

she was killed in her home during hurricane katrina. b.she was relocated to another town after hurricane katrina. c.she died trying to get victims of the hurricane to safety. d.she is still missing — police do not know where she is.