1. For the String class, what’s the difference between «#slice» and «#slice!»? Answers: • None, «#slice» is just an alias for «#slice!». • There is no «#slice!» method in Ruby on Rails. • «#slice» returns a new object, «#slice!» destructively updates — mutates — the object’s value. 2. How to pass variable “projects” into ERB template from controller? Note: There may be more than one right answer. Answers: • @projects = Project.all • render locals: { projects: Project.all } • render projects: Project.all • render :index, projects: Project.all 3. How to permit nester attributes in Rails controllers for such model? class User has_one :profile accepts_nested_attributes_for :profile end Answers: • params.require(:user).permit(:email, profile: [:id, :_destroy]) • params.require(:user).permit(:email, profile: {:id, :_destroy}) • params.require(:user).permit(:email, profile_attributes: [:id, :_destroy]) • params.require(:user).permit(:email, profile_attributes: {:id, :_destro...