A ____ is a network subaddress (assigned a number between 0 and 65,535) through which a particular type of data is allowed to pass.

if-else statements that are inside other if-else statements are said to be _______________.

Fill in the blank(s) with the appropriate word(s).

Used in conjunction with an XML parser that supports data validation, a DTD can be used to accomplish what?

What will be an ideal response?