Which of the following validations in Rails checks for null fields?

Using ERB for views, what filename should be given to a partial called 'login'?

What is output of following statements? 1) '.nil? == '.empty? && '.blank? == '.empty? 2) !'.nil? == '.empty? && '.blank? == '.empty? 3) nil.nil? == nil.empty? && nil.blank? == nil.empty? 4) !'.blank? == '.present? 5) '.any? == !'.empty? 6) '.blank? == '.empty?

For the String class, what's the difference between '#slice' and '#slice!'?

Which controller actions (by default) are best suited to handle the GET HTTP request?

Rails automatically requires certain files in an application. Which of the following files are automatically included without an explicit 'require' being necessary?

The databases supported by ActiveRecord without any other gem are:

What is the purpose of config.ru file?

The best practice says:

How you can load your database with seeded data

MVC stand as: