Order of email send (based on distribution list members)

Good morning Community!!  😀

Does anyone know how Marketo chooses to send emails to a given distribution list? I don't mean "how do I select the criteria". I literally mean "in what order" do the members of a program receive emails (alphabetically? grouped by company? timezone?)....?

If it' not the same across all programs, does anyone know at least what it would be for a nurture program and an email send?

Thanks community!