Problems : Section - 4 (Lab Quiz) Questions

Hello everyone,
In the section -4, Lab Quiz questions, I see this question.
1st) By extension, how many databases are there?
3rd) Are there any databases by MIME type yet?

Now, I can’t understand how can i solve this question? That means, in the first question, How can I find the number of database?
and, third number question, I can’t understand anything.
Can anyone help me?

Here’s a hint: